3ndHydrogen & Energy Symposium

Braunwald, Switzerland 2009rd

3 INTERNATIONALSYMPOSIUM
HYDROGEN & ENERGY
Hydrogen Production, Hydrogen Storage, Hydrogen Applications, Theory andModelling, Fuel Cells, Metal Hydride Batteries, Functional Materialsrd

The 3 symposium “Hydrogen & Energy” follows the inaugural symposium on 16. February 2007 at Empandand the 2 symposium “Hydrogen & Energy” in Braunwald 21. – 25. January 2008. It serves as an
information platform of the fundamental science and the frontiers of research in Sciences and Technologyof Hydrogen & Energy.
The second symposium consists of invited keynote lectures reviewing the key elements of the hydrogen
cycle. The world leading experts present the current research challenges and newest results in invited andcontributing talks. Early stage and experienced researchers present there results and the open questions
on posters as well as in a one slide presentation.

The conference takes place in the hotel Alpenblick in the beautiful small village Braunwald on
1'256 m (Eggstöcke 2'449 m) above see level in the Swiss mountains. The village is free oftraffic, quiet and offers, beside the scientific program, relaxing moments as well as plenty ofsport activities.
The number of participants is limited to 90.

25. - 30. January 2009

Hotel Alpenblick
CH-8784 Braunwald
Tel (+41) (55) 643 1544
URL: http://www.klausen-resort.ch/en/alpenblick.html

PROGRAM

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3nd

Hydrogen & Energy Symposium

PROGRAM

Braunwald, Switzerland 2009

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Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

CONTENTS
Timetable
Abstracts
SUNDAY 25. 1. 2009
Prof. Dr. Heinz Berke
I01: METAL-INDUCED AND METAL-FREE REACTIONS OF DIHYDROGEN AS A BASE FORCHEMICAL HYDROGEN STORAGE

MONDAY 26. 1. 2009
Dr. Gary Sandrock
I02: OVERVIEW OF HYDROGEN STORAGE: GAS, LIQUID, SOLID
Dr. Robert Bowman
I03: SOLID STATE NMR STUDIES OF THE BOROHYDRIDES
Dr. Andreas Borgschulte
O01: THE TANK IS EMPTY
Dr. Adem Tekin
O02: DIFFUSION PATHWAYS OF NH3 IN Mg(NH3)xCl2 FROM DFT CALCULATIONS
Dr. Robin Gremaud
O03: HYDROGEN VIBRATIONS AND DIFFUSION MECHANISM IN H/D EXCHANGED LiBH4
Prof. Dr. Joachim Schoenes
O04: POLARIZATION DEPENDENT RAMAN SPECTROSCOPY OF LiBH4 SINGLECRYSTALS
Dr. Zbigniew Lodziana
O05: STUCTURE AND STABILITY OF BOROHYDRIDES
Dr. Oliver Friedrichs
O06: SYNTHESIS OF LIBH4 BY BORANE ABSORPTION OF LIH
Dr. Elisa Gil Bardaji
O07: MECHANOCHEMICAL AND DIRECT WET CHEMICAL SYNTHESIS OF METAL
BOROHYDRIDES, BORODEUTERIDES AND PARTIALLY DEUTERATED BOROHYDRIDES
Dr. Riccarda Caputo
O08: FIRST-PRINCIPLES STUDY OF METAL BORIDES: ARE THEY INTERMEDIATES ORPRECURSOR COMPOUNDS FOR HYDROGEN STORAGE?
Mr. Claudio Pistidda
O09: A DETAILED STUDY ON THE DEHYDROGENATION OF 2NaBH4+MgH2
Dr. Gemma Garcia
O10: COMBINATORIAL APPROCH FOR THE DISCOVERY OF NEW MATERIALS FOR
HYDROGEN STORAGE
Mr. Sebastiano Garroni
O11: DEHYDROGENATION MECHANISM OF THE 2 NaBH4 + MgH2 PREPARED BY BALLMILLINGPROGRAM3

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TUESDAY 27. 1. 2009
Prof Dr. Ronald Griessen
I04: CAPPED METAL-HYDROGEN SYSTEMS
Prof. Dr. Bengt Kasemo
I05: LSPR AND QCM-D MEASUREMENTS OF HYDROGEN STORAGE IN NANOMATERIALS
Mr. Suleyman Er
O12: HIGH CAPACITY MOLECULAR HYDROGEN STORAGE NANOMATERIALS
Dr. Nicola Naujoks
O13: QUARTZ CRYSTAL MICROBALANCE STUDIES OF HYDROGEN STORAGE IN
NANOSTRUCTURED MATERIALS
Prof. Dr. Mathias Getzlaff
O14: HYDROGEN-INDUCED PLASTIC DEFORMATION OF RARE EARTH METAL THINFILMS AND COMPARISON WITH CORRESPONDING NANOPARTICLES
Dr. Kevin Sivula
O15: NANOSTRUCTURED PHOTOANODES FOR HYDROGEN PRODUCTION BY SOLAR
WATER SPLITTING
Dr. Mauro Palumbo
O16: A THERMODYNAMIC DATABASE FOR HYDROGEN STORAGE SYSTEMSWEDNESDAY 28. 1. 2009
Dr. Geert Brocks
I06: FIRST PRINCIPLES MODELING OF MAGNESIUM TRANSITION METAL HYDRIDES
Dr. Martin Johansson
I07: HYDROGEN SPLITTING STUDIED BY H-D EXCHANGE
Mr. Florian Buchter
O34: EXPERIMENTAL ELECTRONIC CHARGE DENSITY OF LiBH4 FROM MAXIMUMENTROPY METHODProf Wieslawa Sikora
O18: ANALYSIS OF POSSIBLE MAGNETIC STRUCTURES IN ERMN2D2 DEUTERIDEProf Dr. Asuncion Fernandez
O19: A COMPARATIVE STUDY OF THE ADDITIVE ROLE IN THE MgH2-Nb2O5 SYSTEM vs.
THE LiBH4+MgH2-Ti-iso SYSTEM
Dr. Fabrice Leardini
O20: LOW TEMPERATURE HYDROGEN DESORPTION FROM MgH2/Mg(OH)2 SYSTEM
Mr. Hidayet Argun
O21: PHOTOBIOLOGICAL HYDROGEN PRODUCTION FROM DARK FERMENTATIONEFFLUENT

THURSDAY 29. 1. 2009
Prof. Dr. Jens K. Nørskov
I08: ATTEMPTS TO UNDERSTAND ELECTROCHEMICAL, PHOTOCHEMICAL AND
BIOLOGICAL WATER SPLITTING WITHIN THE SAME CONCEPTUAL FRAMEWORKPROGRAM

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Prof. Dr. Bill David
I09: POWDER DIFFRACTION STUDIES OF LIGHT WEIGHT HYDROGEN STORAGE
MATERIALS
Prof Dr. Andreas Züttel
O22: MECHANISM OF HYDROGEN SORPTION IN COMPLEX HYDRIDES
Dr. Valentina Zakaznova
O23: HYDROGEN PRODUCTION BY ALKALINE ELECTROLYSIS: IS THERE A WAY TO
INCREASE ITS EFFICIENCY?
Mr. Daniel Marinha
O24: La0.6Sr0.4Co0.2Fe0.8O3-x MICROSTRUCTURES OBTAINED BY ELECTROSTATICSPRAY DEPOSITION FOR IT-SOFCs
Dr. Ulrich Vogt
O25: HIGH TEMPERATURE ELECTROLYSIS BY SOEC TECHNOLOGY FOR COSTEFFICIENT AND ECONOMICAL HYDROGEN PRODUCTION
Mr. Daniel Wiedenmann
O26: FIB/TEM AND EPMA AS COMPLEMENTARY TECHNIQUES FOR THE INVESTIGATIONOF SOEC AND SOFC
Mr. Shunsuke Kato
O27: IMPACT OF THE SURFACE OXIDATION OF LiBH4 ON THE H2 DESORTPITIONPROCESSES
Mr. Jian-Cheng Chen
O28: H2 DISSOCIATION ON Ti/Al(100) SURFACES
Mrs. Emilie Deprez
O29: SURFACE ANALYSIS AND OXIDATION STATE IN THE REACTIVE HYDRIDECOMPOSITE 2LiBH4+MgH2+Ti-iso
Dr. Jean-Claude Crivello
O30: ELECTRONIC PROPERTIES OF SOME INTERMETALLIC COMPOUNDS AND THEIRHYDRIDES
Dr. Maciej Krystian
O31: KINETICS OF HYDROGEN SORPTION AND DESORPTION IN ECAP-PROCESSED Mg
ALLOY ZK60
Dr. Stefan Schlag
O32: THE GLOBAL HYDROGEN MARKETFRIDAY 30. 1. 2009
Prof. Dr. Bjørn C. Hauback
I10: DIFFRACTION STUDIES OF COMPLEX HYDRIDES
Dr. Jens Oluf Jensen
I11: PEM FUEL CELLS AT ELEVATED TEMPERATURE
Dr. Philippe Mauron
O33: HIGH-PRESSURE AND -TEMPERATURE DSC (DIFFERENTIAL SCANNING
CALORIMETER) FOR COMBINED PCT (PRESSURE, CONCENTRATION, TEMPERATURE)
MEASUREMENTS OF HYDRIDES
Dr. Emmanuel WirthO17: NEW TOOLS FOR THE CHARACTERISATION OF HYDROGEN STORAGE MATERIALSPROGRAM

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Prof. Dr. Hans HagemannO35: VIBRATIONAL SPECTROSCOPY AS A PROBE FOR STRUCTURE AND DYNAMICS OF
INORGANIC BOROHYDRIDES
Dr. Anibal Ramirez-Cuesta
O36: INELASTIC NEUTRON SCATTERING SPECTROSCOPY OF MOLECULAR HYDROGENIN POROUS MATERIALS AND SURFACES
Dr. Arndt Remhof
O37: HYDROGEN DYNAMICS IN LiBH4 STUDIED BY QUASIELASTIC NEUTRONSCATTERINGPOSTER
MONDAY 26. 1. 2009
Mrs. Carine Rongeat
P01: SYNTHESIS OF Ca(BH4)2 BY REACTIVE BALL MILLING
Mr. Christian Bonatto Minella
P02: HYDROGEN SORPTION PROPERTIES OF MODIFIED CALCIUM BOROHYDRIDE
Dr. Daphiny Pottmaier
P03: HYDROGENATION PROCESSES AT LOW PRESSURES IN THE Na-Mg-B SYSTEMPREPARED BY REACTIVE BALL MILLING
Mr. Flavio Pendolino
P04: TRUE ACTIVATION ENERGY OF DECOMPOSITION OF LITHIUM BOROHYDRIDE
LIBH4Dr. Chiara Milanese
P05: IMPROVEMENT IN THE H2 ABSORPTION KINETICS OF THE Mg – Ni SYSTEM BY C
(GRAPHITE) ADDITION
Mr. Filippo Agresti
P06: EVIDENCE OF FORMATION OF LiBH4 BY HIGH ENERGY BALL MILLING OF LiH AND
B IN HYDROGEN ATMOSPHERE
Dr. Ashley Stowe
P07: CATALYTIC ROLE OF NANOSTRUCTURED CARBON ON NaAlH4 HYDROGENSORPTION
Dr. Mitsuru Matsumoto
P08: LIQUID PHASE SYNTHESIS OF MAGNESIUM AMIDE AND AMIDE BASED HYDROGEN
STORAGE MATERIALS
Mr. Pascal Martelli
P09: IDENTIFICATION OF STRUCTURAL PHASES OF Ca[BH4]2 BY NUCLEAR MAGNETICRESONANCE SPECTROSCOPY
Dr. Francesco Dolci
P10: INTERMETIATES IN THE MIXED 2LiNH2/MgH2 HYDROGEN STORAGE SYSTEM
Mr. Deniz Cakir
P11: STRUCTURE AND STABILITY OF Li2xMgy(NH)x+y
Mr. Florian Gebert
P12: LOW TEMPERATURE RAMAN SPECTROSCOPY OF Mg(BH_4)_2 AND Mg(BD_4)_2

PROGRAM

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Dr. Andreas Borgschulte
P13: THE TELLER-REDLICH RULE IN COMPLEX HYDRIDES
Dr. Piotr Szymak
P14: CONTROL OF SUPPLY SUBSYSTEMS OF FUEL CELL STACK
Dr. Józef Malecki
P15: VALIDATION OF A MATHEMATICAL MODEL OF 5kW PEMFC STACK SUPPLIED BY
PURE OXYGEN AND HYDROGEN
Dr. Grzegorz Grzeczka
P16: CONCEPTION OF POWER SYSTEM OF AN UNDERWATER VEHICLE BASED ON
FUEL CELL TECHNOLOGYTUESDAY 27. 1. 2009
Mr. Jérémie Brillet
P17: TANDEM CELL FOR HYDROGEN PRODUCTION: EXAMINING HEMATITE-DSC
ARCHITECTURE STRATEGIES
Mr. Michal Gorbar
P18: DEVELOPMENT OF NEW MEMBRANES FOR ALKALINE ELECTROLYSER CELLSBASED ON INORGANIC MATERIAL
Dr. Agnieszka Kuna
P19: SYMMERTY ANALYSIS OF HYDROGEN RELATED STRUCTURALTRAMSFORMATIONS
Dr. Ali Marashdeh
P20: ALLOYING EFFECT ON H OCTAHEDRAL VS TETRAHEDRAL SITE OCCUPATION IN
Pd-Au: FIRST PRINCIPLES CALCULATIONS AND NEUTRON DIFFRACTION
MEASUREMENTS
Mr. Abdel El Kharbachi
P21: STRUCTURAL CHARACTERIZATION AND THERMODYNAMIC PROPERTIES OF THE
LIBH4-MGH2 SYSTEM
Dr. Chiara Milanese
P22: KINETIC FEATURES IN THE H2 SORPTION BY NaBH4 + MgH2 COMPOSITES UNDERMECHANICAL ACTIVATION CONDITIONS
Dr. Jonathan Morrell
P23: ALKALINE SALT MATERIALS PROPERTY AND AGING STUDY
Dr. Irina Konstanchuk
P24: PECULIARITIES OF HYDROGEN INTERACTION WITH NANOCRYSTALLINEMAGNESIUM
Dr. Marco Vittori Antisari
P25: METALLOGRAPHIC STUDY ON THE ROLE OF CATALYST PARTICLES IN THE
KINETICS OF REACTION BETWEEN MAGNESIUM AND HYDROGEN
Dr. Ashish Khandelwal
P26: INVESTIGATION OF MECHANICAL AND KINETIC STABILITY IN COMPACTED MgH2
BASED SAMPLES
Mr. Siarhei Kalinichenka
P27: STRUCTURAL AND HYDROGEN SORPTION PROPERTIES OF Mg–Ni–Y ALLOYSPREPARED BY MELT SPINNING

PROGRAM

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Mrs. Elsa Callini
P28: MAGNESIUM BY GAS PHASE CONDENSATION:MORPHOLOGY MICROSTRUCTURE
AND HYDROGEN SORPTION
Mr. Katarzyna Morawa
P29: HYDROGEN STORAGE IN LIQUID ORGANIC HYDRIDES
Mr. Jon Bergmann Maronsson
P30: COMPUTATIONAL METHODS FOR DESCRIBING REACTION RATES AT INTERFACES
OF ENERGY MATERIALS
Mr. Thomas Kollin
P31: To be announced
Mr. Ryoji Sahara
P32: STRUCTURAL OPTIMIZATION BY TOMBO: CASE STUDY OF HYDRIDES AND
MOLECULESSCIENCE OF HYDROGEN & ENERGY AWARD
List of Participants
Information
Notes

PROGRAM

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3ndHydrogen & Energy Symposium

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Timetable

PROGRAM

9

PROGRAM

21:00

19:30

Chair

Dinner

O14: Mathias Getzlaff
O15: Kevin Sivula
O16: Mauro Palumbo

O03: Robin Gremaud
O04: Joachim Schoenes
O05: Zbigniew Lodziana

P1 - P14 Poster

A. Borgschulte

P15 - P28 Poster

A. Remhof

DinnerO32: Stefan Schlag

O11: Sebastiano Garroni

Dinner

O31: Maciej KrystianO10: Gemma Garcia

Dinner

O30: Jean-Claude CrivelloO09: Claudio Pistidda

Dinner

O29: Emilie Deprez

O08: Riccarda Caputo

CoffeeO28: Jian-Cheng Chen

O07: Elisa Gil Bardaji
CoffeeB. Kasemo
O27: Shunsuke Kato

Lunch

O26: Daniel Wiedenmann

O25: Ulrich Vogt

O24: Daniel Marinha

O23: Valentina Zakaznova

O22: Andreas Züttel

Coffee

I09: Bill David

I08: Jens K. Norskov

R. Griessen

29.01.2009

Thursday

B. Hauback

Free

Lunch

O21: Hidayet Argun

O20: Fabrice Leardini

O19: Asuncion Fernandez

O18: Wieslawa Sikora

O17: Emmanuel Wirth

Coffee

I07: Martin Johansson

I06: Geert Brocks

R. Bowman

28.01.2009

Wednesday

O06: Oliver FriedrichsSocial event

Lunch

O13: Nicola Naujoks

O02: Adem Tekin

Lunch

O12: Suleyman Er

O01: Andreas Borgschulte

Coffee

I05: Bengt Kasemo

I04: Ronald Griessen

G. Sandrok

27.01.2009

Tuesday

FridayLunch

O37: Arndt Remhof

O36: Anibal Ramirez-Cuesta

O35: Hans HagemannO34: Florian Buchter

O33: Philippe Mauron

CoffeeI11: Jens Oluf Jensen

I10: Bjørn C. Hauback

G. Brocks

30.01.2009

Hydrogen & Energy Symposium

18:00

17:00

Session
Chair
14:00
14:25
14:50
15:20
15:45
16:10
16:35

12:40

I01: Heinz Berke

09:35

10:10
10:35
11:00
11:25
11:50
12:15

I03: Robert Bowman

09:00

CoffeeA. Züttel
I02: Gary Sandrock

Chair

Monday26.01.2009

Sundaynd

25.01.2009

3
Braunwald, Switzerland 200910

3nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Abstracts

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3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Metal-Induced and Metal-Free Reactions of Dihydrogenas a Base for Chemical Hydrogen Storage
H. Berke*, Z. Chen, F. Zou, N. Avramovic, C. Jiang, X. Yang, A. Dybov, X.-Y.
Liu, Y. Zhao, O. Blacque, T. Fox, H.W. Schmalle, K. Venkatesan
Institute of Inorganic Chemistry, University of Zurich, Winterthurer Str. 190, CH-8057 Zurich

Introduction
Chemical reactions of dihydrogen comprisethe classes of hydrogenation/dehydrogenation and hydrodecoupling/dehydrocoupling
and the related process of transferhydrogenation. These transformations may
get involved in chemical hydrogen storage as“fuelling” and “refuelling” processes of thestorage compounds. Most of these reactions
types require splitting of the H2 molecule as
the “activating” step, which can be achievedin two formally distinct ways: Homolytic
splitting: H2→ 2H•, Heterolytic splitting: H2 →H- + H+. Over decades the homolytic splitting
pathways proceeding with oxidative additionof H2 to transition metal centers were
elaborated to a quite high level of
performance. Respective catalyses becameroutine type applications.
As a generic descriptor the term “Ionic
Hydrogenation” (related are “HydridicProtonic
Reactions”
or“Bifunctional
Catalysis”)
describes
the
class
of
stoichiometric and catalytic hydrogenations/dehydrogenations
proceedingwithheterolytic splitting of H2 and withsubsequent hydride and proton transfersfrom Lewis acidic centers (normally transition
metal centers [1] or since recently also maingroup element based [2]) and from (Lewis)
basic centers to unsaturated mostly organic
XY substrates.
H2
X

Cat
Y

E

B

-

H+

X

Y

H

HX

YH

(1)

X = CH2, Y = CH2, O, NR; E = LnM = transition metal fragment or
main group element; B = base

As it appears now there are three distinct
routes for “Ionic Hydrogenations”, which aremechanisticallydistinguishedbythesequence of H transfers: (a) hydride before
proton transfer, (b) simultaneous hydride andproton transfer, (c) proton before hydride
transfer.

Experimental and Results
Within the reaction type (a) we investigatedstoichiometric reactions using hydridic
hydrides, such as WH(CO)n(PMe3)4-n(NO) (n= 0,1) and MoH(dippe)2(NO) complexes(dippe = bis(diisopropylphosphino)ethane), in
combination with alcohols as proton sources
to hydrogenate organic carbonyl compounds.
We recently also studied a catalytic CO2“IonicHydrogenation”
usingaWH(CPh)(dippe)2 complex to afford a mixtureof formic acid and formates in the presenceof a base.
Noyori's and Shvo/Casey hydrogenations ortransfer hydrogenations are good examples
for metal mediated double H transfers of
category (b) [3]. In their essential parts thesepolar processes follow the principal course of
the simultaneous double H transfer describedin eq 2.
X

H

X'

X

Y'

Y

Unsat. II

Unsat. I+Y

HSat. I

H

X'
(2)

+
H

Y'
Sat. II

X,Y and X',Y' = atoms or molecular fragments including
main group and transition elements

Unpolar concerted double H transfers, likethe degenerate reaction of ethane with
ethylene, have high kinetic barriers and are
therefore rarely observed [4], despite the factthat they are symmetry allowed and thermallyaccessible [4 + 2] processes. It became
apparent from our work that the transferred
H’s need to be sufficiently different in12

3rd Hydrogen & Energy Symposium

polarities to enable still concerted and low
energy transition states.
Route (c) occurring with primary H+ transfer
was demonstrated to be operative in olefin,
imine and ketone hydrogenations [5], where
less hydridic transition metal hydrides are
combined with relatively strong proton donorsas H− and H+ sources. Mechanisticallyrelated rhenium and molybdenum catalyzed“Ionic Hydrogenations” of imines, where H2complexes act as proton source, werestudied by us [6]. Related in their reaction
mechanisms are metal-free “Frustrated Lewis
Pair” catalyzed hydrogenations of imines [2],for which a primary proton transfer was
established.

References[1]

H. Jacobsen, H. Berke, in Recent Advancesin Hydride Chemistry, p. 89, Eds. M.

Braunwald, Switzerland 2009

[2]
[3]

[4]
[5]
[6]

Perruzzini, R. Poli, Elsevier, Amsterdam,
Netherlands, 2001.
P.A. Chase, G.C. Welch, T. Jurca, D.W.
Stephan, Angew. Chem. Int. Ed. 42, 2007,
8050.
R. Noyori, S. Hashiguchi, Acc. Chem. Res.
30, 1997, 97; S. E. Clapman, A. Hazdovic,
R. H. Morris, Coord. Chem. Rev. 248, 2004,
2201; Y. Shvo, D. Szarkie, Y. Rahamim, D.
F. Chodosh, J. Am. Chem. Soc. 108, 1986,
7400; C. P. Casey, N. A Strotman, S. E.
Beetner, J. B. Johnson, D. C. Priebe, T. E.
Vos, B. Khodavandi, I. A. Guzei,
Organometallics 25, 2006, 1230.
I. Fernandez, M. A. Sierra, F. P. Cossio, J.
Org. Chem. 72, 2007, 1488.
R.M. Bullock, Chem. Eur. J. 10, 2004, 2366.
X.Y. Liu, K. Venkatesan, H. W. Schmalle, H.
Berke, Organometallics, 23, 2004, 3153; Y.
Zhao, H. W. Schmalle, T. Fox, O. Blacque,H. Berke, Dalton Trans. 2006, 73.

Corresponding author: Heinz Berke, email: hberke@aci.uzh.ch, Tel. (+41) (44) 635 4681

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Monday14

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Overview of Hydrogen Storage: Gas, Liquid, Solid
Gary Sandrock
Metal Hydride Technology, 810 Hacienda Ave., Davis, CA 95616, USA
A hydrogen-based energy system will require stationary, portable and vehicular H-storage systems. The
most technically difficult application is vehicular storage because there are important weight, volume,
charge/discharge rate, safety and cost requirements, among others. This presentation will give a broad
review of the three basic approaches being considered today (gas, liquid and solid), along with the many
subsets of those main categories. Advantages and disadvantages of each technique will be listed, alongwith the present systems status of each and suggestions for future R&D. This talk is aimed at setting thebasic stage for more detailed and focused presentations expected to follow.

Gaseous Hydrogen
Compressed H2 gas is typically stored inadvancedcarbon-fiber-wrapped
epoxy
vessels at 35-70 MPa. This well-establishedapproach suffers from volume and costproblems, among others. The volume
problem can be significantly reduced by thecryogas (cold storage) approach.

Liquid Hydrogen
There are at least four liquid hydrogen
approaches: cryogenic elemental H2, NaBH4
solutions, rechargeable organic liquids andliquid anhydrous NH3. Each approach has
advantages and disadvantages. For all fourof these sub-approaches, the efficiencies andcosts of production and/or regeneration areof concern, along with possible safety
considerations.

Solid Hydrogen
Solid hydrogen can be classified into three
categories.
High surface area adsorbents rely on
physisorption, with relatively weak binding
enthalpies (4-10 kJ/mol H2). Examples
include various carbons, MOFs, zeolites,
clathrate hydrates and certain polymers.
Because of their generally low values of
ΔHads, adsorbants generally require lowtemperatures for effective H-storage. Metal

incorporation offers some hope for increasing
ΔHads.
Non-reversible metal hydrides fall into two
categories: (a) those decomposed byhydrolysis in H2O, and (b) those decomposed
thermally. Although they often have attractive
volumetric and gravimetric H-capacities, aswell as controllable decomposition kinetics,
both categories must be chemicallyregenerated with significant energy penalties.
Reversible metal hydrides offer the best
opportunities for in situ recharging. This
family of solid storage media consists mainlyof metallic and complex (mixed ioniccovalent) hydrides. Although all have goodvolumetric H-capacities, those that also havegood gravimetric capacities usually require
excessive decomposition temperatures and“catalysis” for acceptable reversibility. It is
this particular category of materials wheremost solid-state storage R&D is presently
being performed. There is a focus on metalborohydrides, nanostructure and phasemixtures.

Systems Status
A number of prototype vehicular storage
systems have been built and/or analyzed formost of the storage categories outlined
above. Each has one or more practicalshortcoming. More innovative materials andengineering R&D are clearly needed.

Corresponding author: Gary Sandrock, email: gary.sandrock@sbcglobal.net, tel. (+1) (530) 753 0451

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Solid State NMR Studies of the Borohydrides
R. C. Bowman, Jr.1, S.-J. Hwang2, C. Kim2, J. Ku2, M. S. Conradi3, D. T.
Shane3, R. L. Corey3,4, J. W. Reiter1, and J. A. Zan1
1

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA;
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena
CA 91125 USA; 3Washington University, Dept. of Physics, Saint Louis MO 63130 USA; 4South
Dakota School of Mines and Technology, Rapid City SD 57701 USA
2

High-resolution solid state 11B spectra from LiBH4, Mg(BH4)2, Ca(BH4)2, and LiSc(BH4)4 confirmed there isosimilar bonding for BH4 ions in these hydrides. Following hydrogen desorption at temperatures ≥ 400 C,-2
all of these borohydrides formed variable amounts of the B12H12 species as well as the elemental
amorphous boron (B) or boride (e.g., MgB2, CaB6, etc.) phases. Partial reversibility was noted in LiBH4 +MgH2 mixture and Ca(BH4)2. 1H and 11B relaxation times were also used to assess motions in the low (LT)and high-temperature (HT) phases of LiBH4, Mg(BH4)2, and Ca(BH4)2,

Introduction

Results

Multinuclear nuclear magnetic resonance(NMR) spectroscopy provides novel insights
on the compositions, chemical bonding,
structures, as well as rotational andtranslational motions of complex metal
hydrides. Because short-range interactions
dominate NMR, highly disordered as well as
amorphous materials can often be morethoroughly evaluated than is possible with Xray or neutron diffraction studies that usuallyrequire good crystallinity. Taking examples
from our recent investigations of several
borohydrides, we illustrate how these NMR
techniques resolve diverse issues on phaseformation and decomposition processes.

The presence of the B12H12-2 species
following hydrogen desorption from all theborohydrides was established from the 11B
CPMAS and MQMAS spectra. While theborides MgB2, CaB6, and ScB2 were formedat sufficiently high temperatures, partial
reversibility with H2 gas was only observed
for the Ca system and the mixture of LiH and
MgB2. Formation of B12H12-2 anions inhibits
reformation of the borohydrides. Rotation of
the BH4- ions controls the relaxation times of
LT-LiBH4, Mg(BH4)2, and Ca(BH4)2 while Liion diffusion dominates spin relaxation in HTLiBH4 with an activation energy = 0.7 eV3.

Experimental

Acknowledgments

The solid-state NMR techniques Magic Angle
Spinning (MAS), cross-polarization (CP)MAS, and multi-quantum (MQ) MAS thatwere used to assess these borohydrides andtheir decomposition products were described
previously1,2. The nuclear relaxation times
were measured from 300 K to over 525 K
using the methods reported by Corey, et al.3

These studies were partially supported by DOE
grants DE-FG02-05ER46256 and DE-AI-0106EE11105 and were partially performed at the
JPL, Caltech, under a contract with NASA.

References[1] S.-J. Hwang, et al., J. Phys. Chem. C 112(2008) 3164
[2] J. Purewal et al; J. Phys. Chem. C 112 (2008)
8481[3] R. L. Corey, et al., J. Phys. Chem. C 112(2008) On-line.

Corresponding author: Robert Bowman, email: rcbjr1967@gmail.com Tel. (001) 818-354-7941

16

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

The Tank is empty
A. Borgschulte, C. Rongeat, S. Kato, M. Bielmann, R. Gremaud, A. Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
What might become a problem when using hydrogen as an energy carrier in car, is a scientific challenge incurrent research. A future hydrogen fuel gauge is just an indicator of the amount of hydrogen remaining in
the used metal hydride. In materials research, the determination of pressure-composition isotherms (pcT)
is mandatory to obtain the thermodynamic properties of metal hydrides. Various experimental techniques
to measure the plateau pressures of metal hydrides are reviewed, that is gravimetric and volumetric pcT
measurements, scanning differential calorimetry, and hydrogenography and resistance measurements on
thin films. The agreement of the data for the archetypical example MgH2 is very good. Differences are
explained by kinetic effects of the sorption process. The impact of kinetics on the accuracy of thedetermination of the equilibrium pressure is demonstrated by a comparison of dynamic (flux method) withstatic pcT measurements of LaNi5Hx. The use of optical probes as hydrogen fuel gauge is demonstrated.

Measurement of equilibrium states
The thermodynamic parameters of hydride
formation can be extracted from thetemperature dependence of the equilibriumpressure, by means of the Van ‘t Hoff
relation. The technically challenging problem
is the measurement of such equilibrium
isotherms. In static experiments, thepressure is stepwise enhanced and thesystem equilibrates. Most frequently usedtechniques are scanning methods, in which
one thermodynamic parameter (eitherpressure or temperature) is varied and the
response of the sample is recorded. As thesemeasurements are by definition dynamic
measurements, the equilibrium values haveto be extrapolated. The quality of theextrapolation relies on the modelling of the
kinetics. We will give an insight in theunderlying elementary steps of H-sorption
and apply a quantitative model [1] on various
experimental
examplesmeasuredbydifferent systems.

Indirect Methods
Indirect methods such as hydrogenography[2] and scanning differential calorimetry [3]make use of the impact of the change of thehydrogen content on
properties of the material.

otherphysicalFig. 1. Equilibrium pressures and kinetics of
LaNi5Hx measured gravimetrically.

Optical methods have several advantages,
which make them potential candidates asmethods to be used in hydrogen fuel gauges.

References[1] Borgschulte et al; Phys. Rev. B 78, 094106(2008).
[2] Gremaud et al; Adv. Mater. 19, 2813-2817(2007)[3] Rongeat et al., J. Phys. Chem. B 2007, 111,
13301

Corresponding author: Andreas Borgschulte, email: andreas.borgschulte@empa.ch, Tel. (+41) (44) 823
4639

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3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Diffusion Pathways of NH3 in Mg[NH3]xCl2 from DFT
calculations
Adem Tekina,b, Tejs Veggeb, Jens K. Nørskovaa) Center for Atomic-scale Materials Design (CAMD), Department of Physics, Technical
University of Denmark, DK-2800 Lyngby, Denmark b) National Laboratory for Sustainable
Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark
Ammonia containing metal salts is one of the promising materials to store hydrogen indirectly. They show
a fast and reversible ammonia ab- and desorption kinetics. Mg(NH3)xCl2 with x=6,2,1 is selected as aprototype system to enlighten this phenomenon. Bulk diffusion pathways of ammonia in Mg(NH3)xCl2 isinvestigated by employing a planewave density functional theory approach. Results indicated that diffusion
is much faster in the hexa(x=6) ammine phase.

Introduction
Indirect storage of hydrogen in the form ofammonia stored in metal salts, so-called
metal ammines, has many interesting
properties as an energy storage medium.
Whereas many metal hydrides suffer fromlow density of hydrogen, slow release or apoor reversibility of ab- and desorption ofhydrogen, metal ammines have recently
been shown to display superior properties[1]. In contrast to metal hydrides, metal
ammines decompose thermally by releasing
ammonia which can later be cracked intohydrogen with an ammonia decomposition
catalyst.
One of the most promising metal amminesfor hydrogen storage is Mg(NH3)6Cl2 (9.1 %wt of hydrogen), which has been investigatedboth theoretically and experimentally [2,3,4].
It has been found that this metal ammine
develops a system of nano-sized pores
during ammonia decomposition enabling afast ab- and desorption of ammonia.

Results
We employed a planewave density functional
theory approach using the RPBE generalized
gradient approximation to account for
exchange and correlation effects todeterminediffusionmechanisms
anddecomposition pathways for Mg(NH3)xCl2.
Results are presented for diffusion androtation rates in x=6,2,1, using a combinationof nudged elastic band calculations andtransition state theory, showing that diffusion
is much faster in the hexa (x=6) ammine
phase.

Fig. 1. Ammonia diffusion in Mg(NH3)6Cl2.

References[1] Christensen et al; J. Mater. Chem. 15 (2005)
4106[2] Jacobsen et al; Chem. Phys. Lett. 441 (2007)
255[3] Hummelshøj et al; J. Am. Chem. Soc. 128(2006) 16[4] Vegge et al; Indirect hydrogen storage in metal
ammines, ed. G. Walker, Woodhead
Publishing, 2008.

Corresponding author: Adem Tekin, email: tekin@fysik.dtu.dk, Tel. (+45) 4525 3184

18

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Hydrogen vibrations and diffusion mechanism in H/Dexchanged LiBH4
Robin Gremaud1*, Andreas Borgschulte1*, Z. Łodziana1*, Timmy RamirezCuesta2, Joachim Schoenes3, Paul Hug1°, Andreas Züttel1*
1

Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, *Sec.
Hydrogen & Energy, °Sec. Solid State Chemistry, CH-8600 Dübendorf, Switzerland
2

ISIS facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 OQX, United
Kingdom3

Institute of Condensed Matter Physics, Technical University Braunschweig, Mendelsohnstrasse
3, D-38106 Braunschweig, Germany
The effects of H/D isotope exchange on bulk LiBH4 are studied with Raman, infrared spectroscopy andinelastic neutron scattering. We show that deuterium is exchanged in the BH4- pseudo-molecule attemperature below melting. We are able to detect each individual B(H4-nDn)- unit (n = 1,..,4) and establishthat their relative fraction as a function of deuterium fraction exchanged follows a statistical distribution.
This shows that in molecular solids like the complex hydride LiBH4, exchange of single hydrogen atoms
and its diffusion through the crystal is possible without breaking the molecular unit.

Introduction
LiBH4 is an example of molecular solid, inwhich the pseudo-molecule, BH4-, is ionicallybound to the counter ion Li+. As aconsequence, phonons in LiBH4 can be wellapproximated by so-called “internal” and“external” vibrations, where internal refers to
the motions within the molecular BH4- unit,
and external refers to crystalline vibration of
BH4- and Li+[1].
Raman and infrared
spectroscopy are ideally suited techniques tofollow the effects of H/D exchange, especiallyin the internal vibrations, as the mass change
shifts considerably normal vibrations.

Results
We report on the effect of hydrogen isotope
exchange on bulk LiBD4 with Raman
spectroscopy at a temperature of 83 K. The
experimental results are compared to density
functional calculations of the vibrational
spectra of B(H4-nDn)- (n=1…4) both isolated
and under the influence of the surrounding
lattice.

We focus on the B-D stretching modes, as
they enable us to detect the presence and to
determine the relative fractions of the B(H4nDn) subunits.

Fig. 1. B-D stretching region in the Raman
spectra for LiBD4 and LiB(H0.55D0.45)4. The peaks
labelled as ν1(Dn) (n=1…4) refer to symmetricstretching modes of each B(H4-nDn)- unit.

Reference[1] A. –M. Racu et al.,: J. Phys. Chem. 112, 9716
(2008)

Corresponding author: Robin Gremaud, email: robin.gremaud@empa.ch, Tel. (+41) (44) 823 4933

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3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Polarization dependent Raman spectroscopy of LiBH4
single crystals
J. Schoenes, B. Willenberg and F. GebertInstitut für Physik der Kondensierten Materie, Technische Universität Braunschweig,
D-38106 Braunschweig, Germany
A Raman scattering study of the phonon modes is reported for LiBH4 single crystals. Using the polarization
dependence of the lines the symmetry of the modes is determined, allowing a better comparison and amore reliable assignment to computed phonon frequencies. This leads to the revision of a few former
assignments made from Raman measurements on polycrystalline samples.

Introduction
Vibrational spectroscopy, like IR absorption
and Raman scattering are particularly suited
to study hydrogen bonds, since the lightmass of hydrogen generates high vibrationalfrequencies and the isotope effect on
substitution of deuterium for hydrogen is thelargest of any element [1,2]. In a previous
paper [3] we have reported an extensive lowtemperature Raman scattering study on
LiBH4 and LiBD4 powders. The 27 observedlines have been assigned to phonon modes
within the orthorhombic Pnma structure bycomparing the experimental values to density
functional theory (DFT) values [3].

Experimental
In the present contribution we present for the
first time Raman scattering measurements
on small LiBH4 single crystals. These havebeen identified among the grains of thepowders (Alpha Aesar) by searching for large
polarization dependencies of the Ramanlines.

Results
For optimum orientation Ag modes willappear in a configuration in which theincoming and scattered light have the samepolarization but not in a configuration inwhich the scattered light has a polarization

perpendicular to the incoming light. In
contrast, Bg modes will appear for parallel aswell as for perpendicular polarization, therelative intensity giving indications whether
one deals with B1g, B2g or B3g modes. On thebasis of these new results a few of the former
assignments have to be revised. Among theexternal modes this concerns the mode near
307 cm-1 which is definitely of Ag symmetry
and not of B2g symmetry as had beenconcluded on purely energy arguments.
A second issue is the phase transition to ahexagonal structure at about 380 K. Several
grains of our powder samples did not show
the anticipated changes of the Raman
spectra. We have now succeeded in finding a
few grains which, indeed, display thecharacteristic simplification of the Raman
spectra when the phase transition to thehexagonal phase occurs.

References[1] H. Kierey, M. Rode, A. Jacob, A. Borgschulte,
and J. Schoenes, Phys. Rev. B 63, 134109 (2001)[2] J. Schoenes, A.-M. Racu, M. Rode, and S.
Weber, J. Alloys Compd. 446-447, 562 (2007)[3] A.-M. Racu, J. Schoenes, Z. Lodziana, A.
Borgschulte, and A. Züttel, J. Phys. Chem. A 112,9716 (2008)

Corresponding author: Joachim Schoenes, email: j.schoenes@tu-bs.de, Tel. (+49) (531) 391 5130

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3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Structure and stability of borohydrides
Zbigniew Łodziana and Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
Borohydrides of elements of Group 1 and Group 2 of the Periodic Table form ionic structures (eg. LiBH4,
Mg(BH4)2), while transition metals usually form covalent borohydride molecules that are weakly bounded in
Van der Waals crystals. The structural properties of these materials result from type of bonding between
BH4 molecular units and metal atoms. We will discuss the stability various borohydrides with respect toelectronic bonding and structural properties of compounds.

Introduction
Metal borohydrides form variety of crystalline
structures. They have much better hydrogenstorage capacity than alanates due to low
mass of boron. Unfortunately, at present
borohydrides are considered as irreversiblehydrogen storage media that either posses tohigh decomposition temperature or are
unstable at ambient conditions.

MethodWe report calculations of the stability of
selected borohydrides based on a periodic
density functional (DFT) approach. The
Kohn–Sham wavefunctions were expanded
in plane-wave basis sets with energy cut-off
of up to 900 eV. Brillouin zone sampling was
performed on meshes with a k-point spacingof ~0.03 Å−1. The analysis of the valencecharge of atoms was performed within Baderformalism.

Results
The binary alkali borohydrides, withmonovalent or divalent cations form
crystalline structures with significant chargetransfer between metal cation and BH4molecular unit. The charge on BH4 group
ranges between –0.88e for NaBH4 and –0.80e for Ca(BH4)2. During decomposition ofthese compounds neutral species withcovalent bonds are formed. Borohydrides oftri- or tetravalent metal atoms form closed
molecules where significant overlap of theelectronic density between metal and BH4group is observed. The charge transfer
between species is smaller (charge on BH4group is –0.70e for Y(BH4)3 and –0.46e forTi(BH4)4) and occupied Metal-BH4 bonding
orbitals can be distinguished, as can be seenin the Figure 1.

Fig. 1. The electron density at 0.3 e/Å3 of Y(BH4)3(left) and Ti(BH4)4 (right). Dark sphere is for metal,
light gray for boron and small for hydrogen.

These compounds are bound via weakinteraction and crystalline structures are
unstable even at modest thermodynamic
conditions. Small charge transfer anddirectional bonds indicate that decompositionof metal borohydrides with metal valencylarger than two would produce diborane andhigher borohydrides.

Corresponding author: Zbigniew Lodziana, email: zbigniew.lodziana@empa.ch, Tel. (+41) (44) 823 4083

21

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Synthesis of LiBH4 by borane absorption of LiH
Oliver Friedrichs, Andreas Borgschulte, Shunsuke Kato, Florian Buchter, Robin
Gremaud, Arndt Remhof and Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The solvent free synthesis of LiBH4 from LiH in a borane atmosphere at 120°C and ambient pressures isdemonstrated. The source of borane is a milled LiBH4/ZnCl2 mixture, in which Zn(BH4)2 is generated bymetathesis reaction. The great yield of the reaction of about 74 % LiBH4 shows, that a bulk reaction istaking place upon borane absorption by LiH. This indicates that the formation of B-H bonds is the limiting
step for the formation of LiBH4 from the elements. Therefore, the use of diborane as starting reactant
allows to overcome the reaction barrier for the B-B bond dissociation and explains the rather moderate
synthesis conditions.

Introduction
In this work the solvent free synthesis of
Li[BH4] from LiH in borane atmosphere ispresented [1-2]. The absorption reaction isanalyzed by volumetric Sieverts method,
Raman measurements, X-ray diffraction(XRD) and thermal mass spectrometry(TDS).

formation [3]. With a suitable catalyst
supporting the formation of this bond theformation of borohydrides in general might befacilitated. The new synthesis method may
be applied also for other promising
tetrahydroborate systems [4]. Thereby LiH isreplaced by a different metal hydride as
CaH2 or MgH2 for example. This will beanalyzed in future investigations.

Experimental
Commercial LiH is heated in borane
atmospheregeneratedbythermaldecomposition of Zn(BH4)2. The borane
formationisdemonstratedbyTDS
measurements, while the absorption ofdiborane is monitored by volumetric Sieverts
and Raman measurements. After borane
absorption the product is analyzed by XRD,
in order to determine the newly generated
phases in the material.

Fig. 1. Schematic presentation of the mechanismof Li[BH4] formation from borane absorption of LiH

Results
We have shown for the first time thesynthesis of LiBH4 by a solid gas reaction
between LiH and borane at 120°C andambient pressures. The reaction is clearlytaking place not only on the surface of LiH
but in the bulk, which shows that diffusion is
not the main problem in the formation
process. It indicates that the formation of theB-H bond is the rate limiting step in the LiBH4

References[1] Friedrichs et al.; Angew. Chem. Int. Edit.
(2008) submitted[2] Schlesinger et al.; J. Am. Chem. Soc. 75(1953) 186.
[3] O. Friedrichs et al.; Acta Mater. 56 (2008) 949.
[4] A. Züttel et al.; Scripta Mater. 56 (2007) 823.

Corresponding author: Oliver Friedrichs, email: oliver.friedrichs@empa.ch, Tel. (+41) (44) 823 4153

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3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Mechanochemical and direct wet chemical Synthesis ofMetal Borohydrides, Borodeuterides and pertiallydeuterated Borohydrides
M. E. Gil Bardají and M. Fichtner
Forschungszentrum Karlsruhe, Institut for Nanotechnology, D-76021 Karlsruhe, Germany
Various procedures based on mechanochemical and direct wet chemical synthesis have been used to
11
11
11
11
prepare the compounds Ca( BH4)2, Ca( BD4)2, Mg( BH4)2, Mg( BD4)2 and the partially deuterated
compounds NaBH3D and NaBD3H.

Introduction
Metal borohydrides can assume a variety of
crystal structures depending on the synthesis
and the temperature.1 Elastic and inelastic
neutron diffraction experiments can be auseful tool to obtain structural information ofthese materials. In order to perform thesemeasurements calcium and magnesiumborohydride as well as borodeuteride(enriched isotop 11B) have been synthesized.

For the synthesis of partially deuterated
metal borohydrides, namely NaBD3H and
NaBH3D, the previous reaction has been
modified by using metal hydride or
triethylamine borane, respectively.5

In addition, the vibrational spectra of isotopic
analogous of BH4- in a crystalline
environment can be investigated by using
anharmonic DFT calculations. In order tocompare these theoretical results, NaBD3H
and NaBH3D have been synthesized asprobe molecules.

Results
Mg(11BH4)2 and Ca(11BH4)2 were synthesizedaccording to the metathesis reaction 2,3:
2Na11BH4 + MCl2 Æ M(11BH4)2 + 2NaCl
M = Mg, Ca

The synthesis of the corresponding metalborodeuterides [M(11BD4)2, M = Mg, Ca] wasachieved from the starting compound
Na11BD4. A direct wet chemical synthesis4
from Et3N·11BD3 and metal deuteride led to
the formation of the corresponding metalborodeuterides, too.
MD2 + Et3N·BD3 Æ M(BD4)2 + Et3N
M = Mg, Ca

Fig.1. IR spectra of NaBH4, NaBD3H and NaBD4.

Reaction conditions of each procedure aswell as characterization of the products will
be presented.

References[1] Buchter, et al ; J. Phys. Chem. B 112 (2008)8042[2] James, et al; J Prog. Inorg. Chem. 11 (1970)
99.
[3] Siegel at al;Metal Hydrides, ed. W. M. Mueller,
J. P. Blackledgee and Libowitz G. G., Academic
Press, New York (1968)[4] Fichtner at al; Phys. Chem. C 112 (2008)11575[5] Davis et al; Indiana Academy of Science, 236

Corresponding author: M. Elisa Gil Bardaji, email: elisa.gil@int.fzk.de, Tel. (+49) 7247-82-8909

23

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009First-principles study of Metal Borides: Are theyIntermediates or Precursor Compounds for Hydrogen
Storage?
Riccarda Caputo and Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The importance of alkali and earth-alkali metal borides either as intermediates of the formation reaction of
the corresponding borohydrides either as products of their thermal decomposition to upload hydrogen is
discussed via first-principles calculations. The hydrogenation and de-hydrogenation cycle runs into acertain degree of irreversibility due to polymorphism of metal borides. Among lithium borides, LiB and Li2B6
are reported and discussed and compared with dehydrogenation phases of LiBH4.

Introduction
The hydrogenation of lithium borides, inparticular of LiB[1] and Li2B6 [2] is modelled
and studied from first-principles calculations
using density functional theory based
methods with GGA functional and normconserving type pseudopotential, to modelthe 1s state of both lithium and boron. Fullgeometry optimization is employed as
implemented in CASTEP and CPMD codes.

confirms the inertness to hydrogen of Li2B6
experimentally observed.

Results
The absorption of lithium in the α-phase ofboron is studied at different compositions in
the boron-rich region up to 1:1 atomic ratio
Li:B [3]. As increasing the lithium content, thetypical icosahedron-based structure of pureboron phase is destroyed [4]. Among all thepossible phases so far investigated, LiB and
Li2B6 has the lowest energy with thecorresponding heat of formation equal to-0.249 eV and -0.448 eV per formula unit
respectively, calculated referring to Li (bcc)
and α-boron. The hydrogenation of LiB at low
concentration of hydrogen has a slightendothermic heat of reaction equal to +0.160
eV per formula unit LiBH1.5. The
hydrogenation of Li2B6, at even lower
hydrogen concentration, results a highly
endothermic reaction. In fact the heat ofreaction is equal to +4.994 eV per formula
unit Li2B6H0.8. That high energy of reaction*

Figure 1. (a) LiB optimized structure, (b) LiBH1.5 ,one of the corresponding hydrogenated phase.
(c) Li2B6 optimize structure, (d) the correspondinghydrogenated phase, Li2B6H0.8. (Li, violet, B, pink,
H white).

References[1] Wörle, M. et al., Z.Anorg. Allg. Chem., 632 (2006)1737.
[2] Mair, G., et al., Z. Anorg. Allg. Chem., 625 (1999)
1207.
[3] Caputo, R. and A. Züttel, (to be submitted).
[4] Caputo, R. and A. Züttel, (submitted) to Phys. Chem.
Chem. Phys.

Corresponding author: Riccarda Caputo, email: Riccarda.Caputo@empa.ch, Tel. (+41) (44) 823 4422

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3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

A detailed Study on the Hydrogenation of 2NaH + MgB2
Claudio Pistiddaa, Gagik Barkhordarianb, Sebastiano Garronic, Christian Bonatto
Minellab, Torben Jensend, Martin Dornheimb, Wiebke Lohstroha, Rüdiger
Bormannb, Maximiliam. Fichtnera.
aInstitut für Nanotechnologie, Forschungszentrum Karlsruhe GmbH, Postfach 3640, 76021
Karlsruhe, GermanybInstitute of Material Research, GKSS Research Centre Geesthacht GmbH, Max Planckstrasse 1, D-21502 Geesthacht, GermanycDepartament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, SpaindInterdisciplinary Nanoscience Centre (iNANO) and Department of Chemistry, University of
Aarhus, Langelandsgabe 140, DK-8000. Denmark

The recent discovery of the unique kinetic property of MgB2 in facilitating the hydrogenation of light metal
complex borohydrides at moderate conditions has created new prospects to develop high capacity low
enthalpy hydrogen storage materials. These new composite materials which consist of a binary light metal
hydride (like LiH, NaH and CaH2) and MgB2 can be hydrogenated in much more moderate conditions
compared to the usual route of hydrogenating the mixture of the corresponding binary hydride and pure
Boron. This suggests that MgB2 is kinetically superior to pure Boron in these reactions; however thecorresponding mechanisms are not yet understood. With the aim of clarifying the function of MgB2
functions, we investigated the hydrogenation of NaH+MgB2 by in-situ Synchrotron X-ray diffraction, highpressure titration, and HP-DSC.

Introduction

strongly dependentpressure.

onthehydrogenIn the present work the hydrogen desorption
behavior of the RHC system 2NaH+MgB2
prepared by ball milling was investigatedExperimental
NaH (95% purity) and MgB2 (99.99% purity)
were purchased from Sigma Aldrich and AlfaAesar, respectively. The NaH and the MgB2
were charged into a hardened steel vial andmilled for 1 hour in a Spex 8000 ball mill, witha ball to powder ratio 10:1.Results
An extensive in-situ PXD study during
absorption of the RHC system 2NaH + MgB2
prepared by BM was performed. The results
revealed that the formation of NaMgH3 isFig. 1. Series of SR-PXD patterns of the
2NaH+MgB2 system heated under 50 bar ofhydrogen pressure from RT to 400°C.

Corresponding author: Claudio Pistidda, email: claudio.pistidda@int.fzk.de25

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Combinatorial Approach for the Discovery of new
Materials for Hydrogen Storage
Roger Domènech-Ferrer, Gemma Garcia, Alfonso Sepulveda and Javier
Rodriguez-Viejo †Nanomaterials and Microsystems Group, Department of Physics, UAB, Campus UAB,
Bellaterra, 08193 Spain†

MATGAS AIE, Campus UAB, Bellaterra, 08193 Spain

We have developed and tested a thin film membrane-based calorimeter to measure kineticallylimited phase transitions such as the de/hydrogenation of metallic hydrides. Those
microsystems are used as substrates for singular and combinatorial metal hydrides thin film
deposition and tested for hydrogen storage applications.

Introduction
The combinatorial approach provides a mean
to quickly investigate a large number of
unexplored material for Hydrogen storage
combining high throughput synthesis andscreening methodologies [1-3]. Furthermore,thin film techniques offer a uniquemethodology for studying the nanoscale andinterphase effects on the materials
properties.

Experimental
We have grown thin film libraries of the Mgbased system using a sequential depositionof pure elements (for instante Mg and Al) byan electron-beam evaporation technique [6].
Presently, we are also growing compositional
graded libraries using a co-sputtering
technique. Besides, we have developed thinfilm membrane-based calorimeters that canbe used to characterise (de)hydrogenation
reactions of metallic hydrides [5].

Results
Those Microsystems are used as substrates
for singular and combinatorial metal hydride
thin film deposition, mainly magnesiumbased alloys. After several hydrogenation
treatments at different temperatures to

induce the hydride formation, we observe asignificant reduction in the onset of
dehydrogenation for Mg80Ti20 compared withpure Mg or Mg/Al layers, which confirms thebeneficial effect of Ti on dehydrogenation. By
using libraries containing different Mg-Al
ratios we have also found indirect evidenceof the formation of the alanate phase andthat aluminum can act as a catalyzer for thehydrogenation
reaction.
Actually,
tocomplement the high-throughput screening
we are developing the Thermal Imaging
Technique not only on standard thin films but
also coupled with calorimetric in-situ
experiments.

References[1] C.H. Olk, G.G. Tibbetts, D. Simon, J.J.
Moleski, J. Appl Phys 94, 720–5 (2003).
[2] R. Gremaud, C.P. Broedresz, D. Borsa, A.
Borgschulte, P. Mauron, H. Schreuders, Adv
Mater 19, 2813–7 (2007)[3] S. Guerin, B. E. Hayden, D. C. A. Smith
J. Comb. Chem., 10 (1), 37–43 (2008)[5] A. Sepúlveda, A.F. Lopeandía, R. DomènechFerrer, G. Garcia, F. Pi, J. Rodríguez-Viejo, F.J.
Muñoz; Inter. J. of Hydrogen Energy 33, 2729 –
2737 (2008)[6] G. Garcia, R. Domènech-Ferrer, F. Pi, J.
Santiso, J Rodriguez-Viejo; J Combinatorial Chem
9, 230–6,(2007)

Corresponding author: Gemma Garcia, email: gemma@vega.uab.es, Tel. (+34) 935811481

26

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Dehydrogenation Mechanism
prepared by Ball Millingof

2NaBH4+

MgH2

S. Garroni1, C. Pistidda2, M. Brunelli3, G. Vaughan3, S. Suriñach1, M.D. Baró1
1

Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain

2

GKSS Research Centre, Geesthacht, Germany

3

ESRF European Synchrotron Radiation Facility, BP220, Grenoble, France

Hydrogen storage materials based on a mixture of complex and light metal hydrides constitute a class ofcompounds promising in the field of hydrogen storage for vehicular applications [1]. Particular attention
has been paid recently to Reactive Hydride Composites (RHC), where the combination of an alkaline
borohydride with a reactive hydride induces a thermodynamic destabilization and a decrease of hydrogen
desorption temperature with respect to the component phases [2,3]. Although numerous studies arereported in literature for these functional hydrogen compounds, their dehydrogenation mechanism is notquite clear and their preparation has to be optimized.

Introduction
In this work we focus on the properties of thesystem NaBH4 - MgH2 prepared by highenergy ball milling. The aim of the work is to
study which phases evolve during thehydrogen desorption in the mixture 2NaBH4 +MgH2 in order to understand the mechanismthat is involved in that process.

of Mg appear. The desorption is complete
after 388ºC, in according with the DSC
analysis performed previously.

Experimental
The mixture was milled in a mol ratio 2:1 bymeans of Planetary Fritsch P5 mill. The
milling was performed under pure Argon
atmosphere with a ball to powder ratio of
1:10 and a rotation speed of 230 rpm. With
the aim of characterizing the samples, themorphology, thermodynamic and microstructural properties were investigated by
Scanning Electron Microscopy (SEM),
Differential Scanning Calorimetry (DSC) and
Powder X-ray Diffraction (PXD), respectively.
In addition in situ Powder X-ray Diffraction(SR-PXD) was performed in order toevaluate the phases evolved during thedesorption process.

Results
As shown in fig. 1, after 337ºC the desorptionof MgH2 starts and consequently the peaks

Fig. 1. “in situ” XRD patterns measured at different
temperatures (25-500º) of 2NaBH4 + MgH2
intimate mixture.

Further analysis confirmed that the formationof MgB2 starts after the complete desorptionof MgH2.

References[1] Materials Go/No-Go Decisions Made Within the
Department of Energy Metal Hydride Center of
Excellentce(MHCoE),
SandiaNational
Laboratories, Livermore, CA 94551, 2007.
[2] John J. Vajo and Gregory L. Olson, Scripta Mater,(2007) 56, 829-834.
[3] G. Barkhordarian, T. Klassen, M. Dornheim, R.
Bormann, J. Alloys. Comp., (2007), 440, L18-L21.

Corresponding author: Sebastiano Garroni, email: sebastiano.garroni@campus.uab.cat, Tel. (+34) (93) 5811657

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Tuesday28

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Capped Metal-Hydrogen Systems
Ronald Griessen, Andrea Baldi, Yevheniy Pivak, Herman Schreuders andBernard Dam
Physics Department, VU university, Amsterdam, the Netherlands
In thin films and nanoclusters the surface to volume ratio is much larger than in polycrystalline bulk
materials. We show that the thermodynamics of a Mg layer sandwiched between transition metal (TM)layers can be drastically modified by the elastic constrain imposed by a surface TM layer. The same
applies for Mg nanoclusters with a hard MgO surface layer.

Introduction
Many attempts have been done to destabilize
Mg-hydride. We show here that the plateaupressure of Mg-H can be increased by morethan one order of magnitude by restricting
the free expansion of Mg during hydrogen
absorption. One effective way to do so is bysandwiching Mg layers between transition
metal layers. Another way is by coating
nanocrystallites of Mg by a thin layer of a
hard material.

Experimental
Ti/Mg/Pd multilayers are deposited on glassin a UHV system (base pressure = 10-8 mbar)
by DC/RF magnetron in argon atmosphere.
The thickness of the Ti and Pd layers is 10
and 40 nm, respectively, while the thicknessof the Mg layer is varied from 10 to 40 nm.
This set of samples is used to demonstrate
the effect of elastic clamping. The p-c
isotherms at 333 K are measured by meansof hydrogenography.

hampered by the transition metal layers. Thismodel predicts that

where ps and pf are the plateau pressures ofa sandwiched (s) and a free (f) Mg layer,
respectively. EMg and EMg are the Youngmoduli and dMg and dMg the thicknesses ofthe Mg and TM layers. The parameter adepends on characteristic properties of the
Mg-H system.
A similar model predicts that Mg nanoclusters covered by a thin MgO surface layer
have a plateau pressure at 333K that is
approx. 100 times higher than the plateau ofa pure Mg film.

Results
The width of the plateaus in Fig.1 is
proportional to the thickness of the Mg layerthatbecomestransparentinthehydrogenated state. Most interesting is thelarge increase in plateau pressure withdecreasing Mg thickness. This is predictedby a model in which the lattice expansion of
the Mg layer during H uptake is elasticallyFig. 1. P-c isotherms at 333 K of a Mg layer
sandwiched between Ti and Pd as a function of
the Mg layer thickness (10 – 40 nm).

Corresponding author: Ronald Griessen, email: griessen@nat.vu.nl, Tel. (+31) (20) 598 7915

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LSPR and QCM-D Measurements of Hydrogen Storage
in nano-Materials.
C. Langhammera, N. Naujoksa, E. Larssona, L. Romanszkia, M. Rodahlb, M.
Zächa, V. Zhdanova,c, I. Zorica, B. Kasemoaab

Department of Applied Physics, Chalmers, SE-412 96 Gothenburg, Sweden, Q-Sense AB, 426 77 Vaestra Froelunda,c
Sweden, Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk 630090, Russia

We report (i) QCM measurements of hydrogen uptake/release in submonolayer arrays of Pd
nanoparticles, (ii) LSPR measurements on the same system, (iii) preparation of new
nanoparticle model systems for QCM and LSPR measurements, (iv) a new experimental set up
for QCM measurements with HSM materials and (v) theoretical modeling of hydrogen uptake
kinetics in nanoparticles.

Introduction
Hydrogen storage materials (HSM) in theform of nanoparticles (NP) and nanostructured materials are interesting from theviewpoints of basic physics and applications,and because the thermodynamics andkinetics of the HSM can be modified. A
challenge working with small, well-defined
NPs is the often limited amount of material
available, and the associated reduced
sensitivity. We apply QCM, Localized
Surface Plasmon Resonance (LSPR)
sensing,
associatedpreparation,
andmodeling to study nano-particle HSM.

Experimental
QCM: The QCM technique is wellestablished since long for HSM studies 1. The
sample to be studied is deposited on thesurface of a piezoelectric quartz crystal
sensor, acting as a resonator, allowing
measurement of very small frequency (mass)changes, caused by hydrogen uptake or loss.
LSPR: LSPR is the optical response causedby collective oscillations of conduction band
electrons (plasmons) in a confined particle <light wavelength. Changes in the dielectric
environment of the NP, or a change in the
NP’s electron structure, cause a change inthe optical response which is frequently used
for biosensing. We have recently shown that
this can be used to sensitively measurehydrogen uptake
nanoparticles2.

andreleasein

Pd

Results
Combined QCM and LSPR measurementson relatively large Pd NPs demonstrate (i)that thermodynamic values (enthalpy andentropy) for the alpha and beta phases of Pd
bulk can be obtained by both methods. The
LSPR, calibrated by QCM, has superiorsensitivity and can be used to follow fast
kinetics in both phases. For sufficiently small
particles, interesting new thermodynamics
and kinetics are observed, partly addressedalso by modeling3. We further give a
progress report on a new measurement
system for QCM measurements of HSM, andthe associated sample preparation toincrease the sensitivity of the QCM
measurements (see presentation by Naujocs
et al).

References[1] G. A. Frazier, R. Glosser, J. Phys. D : Appl.
Phys., 12, (1979).; J. Rydén et. al., J. LessComm. Met., 152, 295-309, (1989).; I.
Kulchytskyy et. al., Appl. Phys. Lett., 91,
113507, (2007).
[2] C. Langhammer et. al., Nano Lett., 7, 31223127, (2007).
[3] V. P. Zhdanov, B. Kasemo, Chem. Phys. Lett.,
460, 158, (2008), and tentatively new results.

Corresponding author: Bengt Kasemo, email: kasemo@chalmers.se Tel. (+46) (31) 772 33 70

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3rd Hydrogen & Energy Symposium

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High Capacity Hydrogen Storage Nanomaterials
Süleyman Er1, Gilles A. de Wijs2 and Geert Brocks1
1Computational Materials Science, Faculty of Science and Technology and MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
2

Electronic Structure of Materials, Institute for Molecules and Materials, Faculty of Science,
Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
In the first part, lithiated carbon and oxygen
molecular structures are considered forhydrogen storage applications. Using First
Principles calculations we predict theinteraction of hydrogen molecules with suchmaterials. Within these compounds it is foundthat the Li atoms connected to a central C or
O atom bear partial positive charges.
Hydrogen molecules are then clusteredaround these Li atoms via electrostaticinteractions (Fig.1). According to our
calculations such molecules can attachhydrogen up to ~40 wt. % with averagehydrogen binding energies between 0.1 and
0.2 eV/H2. However, to maintain a reversible
system, molecular dimerization need to beprevented. Here, we consider attaching thelithiated molecular structures to graphene.
The immobilized molecules have a similarinteraction with hydrogen molecules as freemolecules. However, hydrogen weightpercentages are reduced to 5-8 wt. % due tothe additional weight of the graphitic
template.

In the second part, we discuss the hydrogenstorage properties of novel boron sheets[1]and buckyballs[2]. We find that the interactionof molecular hydrogen with these systems is
weak as in the case of carbon basedgraphitic and buckyball structures. However,both of the boron structures bind tolightweight alkali and some of alkaline earth
metals strongly. Deposited metals on thesurface of boron systems bind severalhydrogen molecules (Fig.2). Hydrogenweight percentages and binding energies
vary depending on the choice of the metal.
Ca is found to be a promising doping element
for both of the boron sheet (6wt. %H, 0.15
eV/H2) and buckyball (9 wt %H, 0.11 eV/H2)
structures.

Fig. 2. Boron buckyball doped with 12 Ca atoms in
its fully hydrogenated stage.

Fig. 1. CLi4 (left side figure) and OLi2 molecules intheir fully hydrogenated stages.

References[1] H. Tang and S. Ismail-Beigi, Physical Review
Letters 99, 115501 (2007).
[2] Szwacki et al. , Physical Review Letters 98,
166804 (2007).

Corresponding author: Süleyman Er, email: s.er@utwente.nl , Tel. (+31) (53) 489 3167

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Quartz Crystal Microbalance Studies of Hydrogen
Storage in nanostructured Materials
Nicola Naujoks, Loránd Románszki, Michael Zäch, and Bengt Kasemo
Chalmers University of Technology, Applied Physics, SE-412 96 Göteborg, Sweden
Nano-structured materials (thin films and nanoparticles) are investigated regarding their (de-)/hydrogenation properties with the help of Quartz Crystal Microbalance (QCM).

Introduction
Reducing the geometrical dimensions ofhydrogen storing materials to the nanoscale
is expected (and shown) to result inadvantageous kinetics. One approach to
study this effect is to observe thehydrogenation properties of thin metal films[1] and nanostructured metal particles [2]with the help of a Quartz Crystal
Microbalance (QCM). By detecting shifts inresonance frequency the QCM enables themeasurement of minute mass changes that
correspond to a fraction of monolayer ofhydrogen atoms.

the H2 gas. We will further present a new
QCM gas cell setup that will enablemeasurements over a wider range oftemperatures and pressures.

Fig. 1. The samples – thin metal films - aredeposited onto quartz crystal sensors.

Model experiments / QCM
To be studied in a QCM setup, the sample
structures have to be fabricated onto thesurface of quartz sensor, as shown in Fig.1.
The feasibility of the QCM technique toinvestigate hydrogenation of thin metal films
is demonstrated at the example of a Pd
covered Mg film. Fig.2 shows thermodynamic
data of obtained with a QCM setup.
Applying this technique to the investigation ofhydrogen storage in nanoparticles (NP)requires a method of attaching a sufficiently
large amount of NPs onto the crystal (a 2ddisperse layer on the sensor surface suffersfrom a limited sensitivity of the QCM). First
results on embedding hydrogen storing NPs
into porous supports that are coated onto the
crystal will be presented, thereby allowing alarger number of particles to be accessed by

Fig. 2. Hydrogenation and dehydrogenation cycleof a sandwich structured sample (Pd and Mg)

References[1] A. Krozer, and B. Kasemo; J. Less Comm.
Met. 160 (1990). 323.
[2] Langhammer C., Zoric I. and Kasemo B; Nano
Lett. 7 (2007) 3122.

Corresponding author: Nicola Naujoks, email: naujoks@chalmers.se, Tel. (+46) (31) 772 3331

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Hydrogen-induced plastic Deformation of Rare Earth
Metal Thin Films and Comparison with corresponding
Nanoparticles
Mathias Getzlaff1, Astrid Pundt2
1. Institute of Applied Physics, University of Düsseldorf, D-40225 Düsseldorf, Germany
2. Institute of Materials Physics, University of Göttingen, D-37077 Göttingen, Germany
The hydrogen induced plastic deformation processes of Gd metal thin films are determined on thenanometer scale by means of the corresponding surface modifications. These results are compared tohigh Gd islands representing nanoparticles being clamped to the substrate at the interface.

Experimental
Surface modification of thin Gd films and highislands representing nanoparticles during hydrogen adsorption as well as absorption has
been investigated on the nanometer scale bymeans of scanning tunnelling microscopy.

Results
The adsorption occurs in two steps. It is
initiated by surface imperfections (see leftpart of Fig. 1). Starting from these nucleation
centers a domain-like spreading is present
which is strongly hindered at surface steps(see right part of Fig. 1).

Fig. 1. Gadolinium islands on a W(110) surface.
The bar corresponds to 100 nm. Left: The system
was exposed to 0.2 L hydrogen. Hydrogen isadsorbed at that areas appearing deeper which isdue to an electronic effect. Right: With increasing
amount (1 L) a domain-like spreading occurs.

The measurements have shown that during
further hydrogen loading two different typesof surface pattern develop above a particularconcentration: disc-like islands and slope
fields (see Fig. 2).

Fig. 2. Gadolinium thin films on a W(110) surface.
The system was exposed to 70 L hydrogen. Two
different patterns occur: disc-like islands (upperpart) and slope fields (middle part).

These surface patterns can be well describedby two plastic deformation processes in thefilms that lead to glide steps on the film surface. First, the emission of dislocation loops
during hydride precipitation occurs. Secondly, misfit dislocations near the film-substrateinterface are present. Since plastic deformation leads to stress release a lot of thin metal
films being clamped to a substrate relax plastically after reaching a certain hydrogen-induced stress that corresponds to a critical hydrogen concentration. This conclusion is corroborated due to free-standing Gd islands
being without structural deformation.
Overall, combining the ability of preparing
high-quality epitaxial thin films with thedetailed analysis of the mechanical properties during hydrogen absorption may lead toa deeper fundamental understanding of hydrogen switchable thin films. It may also
improve their industrial applications.

Corresponding author: Mathias Getzlaff, email: getzlaff@uni-duesseldorf.de, Tel. (+49) (211) 81 12291

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3rd Hydrogen & Energy Symposium

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Nanostructured Photoanodes for Hydrogen Production
by Solar Water Splitting
Kevin Sivula, Scott C. Warren, Florian le Formal, Adriana Paracchino, Jeremie
Brillet, and Michael Grätzel
Laboratoire de Photonique et Interfaces, Ecole Polytechnique Fédérale de Lausanne, CH-1015,
Lausanne, Switzerland
Recently we have reported nanostructed, silicon doped Fe2O3 photoanodes prepared by atmosphere2pressure CVD which exhibit a remarkable photocurrent under standard conditions (2.2 mA/cm at 1.23 V
2
vs RHE and AM 1.5G 100 mW/cm simulated solar illumination). When these transparent photoanodes are
combined with a bias-supplying photovoltaic cell (a dye sensitized solar cell), unassisted solar-to-hydrogen
conversion efficiencies of 3.3 % can be obtained. Here we will describe the current research efforts of
PECHouse, the Swiss photoelectrochemical centre of excellence, in continuing the development of thesenanostructured photoanodes for solar hydrogen production.

Introduction

process conditions affect the nanostructure
and crystalinity.

The world’s most abundant renewableenergy source, the Sun, has the potential tomeet current and future energy needs. The
direct hydrogen production by waterphotoelectrolysis from solar illumination is
one promising route to directly convert solar
energy into a storable and transportablemedium, but a scalable and inexpensive
photoelectrolysis strategy is essential. Due toits abundance, environmental stability, andfavorable bandgap, iron (III) oxide (hematite)
is a promising photocatalyst for thisapplication. However, the poor photon
absorptivity and charge carrier transport ofhematite have remained obstinate limitations
preventing its full exploitation.

Results

Experimental
Nanostructed,
silicon
doped
Fe2O3
photoanodes were prepared by theatmosphere pressure chemical vapor
deposition from Fe(CO)5 and Si(OC2H5)4.
The
process
temperature,
dopantconcentration, and the growth time werevaried in order to determine the major factors
which influence performance. High resolution
electronmicroscopy,
impedance
spectroscopy and micro Raman analysis
were subsequently used to reveal how theWe show film growth during deposition to belinear with an incubation time. No concern
with electron transport for films up to 600 nm
is found, but a higher recombination rate ofphoto-generated carriers in the hematite near
the interface with the fluorine doped tin oxide,
as compared to the bulk section of the film isnoted. The observed feature sizes of the film
are found to depend strongly on thistemperature and the presence of silicon
dopant precursor (TEOS). We also findevidence for an unusually high donor density
which allows the formation of a space-charge
field inside the nano-sized features of thepolycrystalline
hematite
photoanode—afactor which could play a major role in theseparation of charges and enhancement of
performance, even in the surface features of
5 nm.

References[1] Kay et al; J. Amer. Chem. Soc. 128 (2006)
15714[2] Cesar, et al; J. Amer. Chem. Soc. 128 (2006)
4582[3] Gratzel, M., Nature, 414 (2001), 338

Corresponding author: Kevin Sivula, email: kevin.sivula@epfl.ch, Tel. +41 (0) 21 693 3669

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A thermodynamic Database for Hydrogen storage
Systems
M. Palumboa,b, J. Urgnanib, J. F. Torresb, D. Baldissinb, M. BariccobaParticle Simulation and Thermodynamics Group, Computational Materials Science Center(CMSC), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki, 3050047, Japanb

Dipartimento di Chimica I.F.M. and NIS/INFM/CNISM, Università di Torino, via Giuria 7/9,
10125 Torino, Italy
The thermodynamic behaviour of hydrogen related systems has been investigated by coupling the
CALPHAD approach and ab initio calculations. Several binary and ternary systems have been considered,including La-Ni-H, Al-Mg-H, Na-B-H. The development of a thermodynamic database for hydrogensystems is on going.

In the latest years, hydrogen storage inintermetallic compounds has been proposed
as a suitable way to accumulate energy forseveral applications [1]. However, thediffusion of this technology, especially in theautomotive industry, has been hindered bysome difficulties and limitations. Many
researchers are active nowadays in this fieldtrying to overcome present drawbacks.
To
thispurpose,knowledgeofthermodynamic stability of these compounds
ismuch
helpful
to
study
the
hydrogenation/dehydrogenation process. In
order to be suitable for applications thethermodynamic stability of a candidate
material should not be to high, thus avoiding
a large heat absorbed/released duringhydrogenation/dehydrogenation. Moreover,thermodynamics and phase diagrams areuseful to rationalize synthesis reactions ofthese compounds and to suggest possible
alternative reaction routes. By mixing someof these hydrides with other compounds, it ispossibletomakeeasierthehydrogenation/dehydrogenation process. A
thermodynamic analysis is very useful inrationalizing this behaviour and the
CALPHAD approach is the most suited tothis goal.

The purpose of this work is to develop a
consistent thermodynamic database forhydrogen storage systems. The La-H and LaNi-H phase diagrams have been reviewed
and thermodynamically assessed using the
CALPHAD method, while other binary
systems (Ni-H and La-Ni) have been adapted
to be incorporated in the present database.
Other
Al,
Mg,
Na,
B-basedcompounds/systems of interest for hydrogenstorage are also included [2-5]. For example,
theAl-Mg-Hsystemhas
beenthermodynamically assessed including themagnesium alanate Mg(AlH4)2 which has atheoretical hydrogen content of 9.3 wt% [4].
A
criticalassessmentofavailable
experimental data has been performed. Key
ab initio calculations have been carried out.
Calculated and experimental thermodynamic
properties have then been compared and asatisfactory agreement has been achieved.

References[1] L. Schlapbach et al; Nature 414 (2001) 353[2] K. Zeng et al; IJHE 24 (1999) 989[3] B.-M. Lee et al; J. Alloys Compd. 424 (2006)
370[4] M. Palumbo et al; CALPHAD 31 (2007) 457[5] J. Urgnani et al; IJHE 33 (2008) 3111

Corresponding author: Mauro Palumbo, email: PALUMBO.Mauro@nims.go.jp

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Wednesday36

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009First Principles Modeling of Magnesium Transition
Metal Hydides
Süleyman Er,1 Michiel J. van Setten,2,3 Dhirendra Tiwari,1 Gilles A. de Wijs,2Geert Brocks1
1Computational Materials Science, Faculty of Science and Technology and MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, the Netherlands.

2

Electronic Structure of Materials, Institute for Molecules and Materials, Faculty of Science,
Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands.
3

Institut für Nanotechnologie, Forschungszentrum Karlsruhe, P.O. Box 3640, D-76021
Karlsruhe, Germany.
Lightweight metal hydrides are strong candidates for future hydrogen storage materials. Alloying Mg withlightweight transition metals (TM = Sc, Ti, V, Cr) could provide a viable route towards materials with fast(de)hydrogenation kinetics and suitable thermodynamic properties. We study the structure and stability of
MgxTM(1-x)H2, x = [0,1] by first-principles calculations. The stability of these compounds decreases along
the series Sc, Ti, V, Cr. The dehydrogenation enthalpy of .MgxTi(1-x)H2 can be markedly improved byadding Al or Si, which destabilizes the hydride, whereas it stabilizes the alloy. MgxTi(1-x)H2 also hasremarkable optical properties, such as a black state. We argue that the black state is an intrinsic propertyof these compounds, unlike similar optical phenomena observed in other metal hydride films.

Introduction
MgH2 has been studied intensively since it
has a relatively high hydrogen gravimetricdensity of 7.7 wt.%. Bottlenecks in its
application are its thermodynamic stability
and slow kinetics. Alloying Mg with earlytransition
metals
(TMs)
is
found
experimentally to increase the hydrogenation
kinetics. Here we study the structure, thethermodynamics and the optical properties ofmagnesium transition metal hydrides by firstprinciples calculations at the level of density
functional theory.

Results
We find that the experimentally observed
sharp decrease in hydrogenation rates of
MgxTM(1-x)H2 for x > 0.8 correlates with aphase transition from a fluorite to a rutile
phase. Varying the transition metal (TM) andthe composition x, the formation enthalpy canbe tuned over the substantial range 0-2
eV/f.u. Assuming however that the alloy does

not decompose upon dehydrogenation, theenthalpy
associatedwithreversiblehydrogenation of compounds with a highmagnesium content (x = 0.75) is close to thatof pure Mg [1]. Adding Al and Si to MgxTi(1x)H2, however, destabilizes the hydrides,
whereas it stabilizes the MgxTi(1-x) alloy [2].
Thin films of MgxTi(1-x)H2 show an optical
black state upon hydrogenation. We
calculate the dielectric function and theoptical properties of MgxTi(1-x)H2, x = 0.5,
0.75, 0.875, and argue that the black state is
an intrinsic property of these compounds [3].
In particular, the plasma frequency drops
below 1 eV in disordered structures, whichthen show a low reflection and transmission
in the range 1-6~eV, i.e. a black state.

References[1] Er et al; Phys. Rev. B, submitted (2008).
[2] Er et al; in preparation (2009).
[3] van Setten et al; Phys. Rev. B, submitted(2008).

Corresponding author: Geert Brocks, email: g.brocks@tnw.utwente.nl, Tel. (+31) 534893155

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3rd Hydrogen & Energy Symposium

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Hydrogen splitting studied by H-D Exchange
M. Johansson
Danish National Research Foundation's Center for Individual Nanoparticle Functionality (CINF),
Department of Physics, Technical University of Denmark (DTU), 2800 Lyngby, Denmark
It is shown how the H-D exchange reaction can be utilized to measure the splitting rate of hydrogen at 1
bar. Examples of results are given for transition metals, metal alloys and supported metal nano-particles.

Introduction
The H-D exchange reaction offers aconvenient way to measure the rate ofhydrogen splitting on surfaces at atmosphericpressure. Such measurements can help
understanding the anode processes of theProton Exchange Membrane Fuel Cell
(PEMFC), and could potentially be usefulwhen designing systems for storage ofhydrogen in solids.

Experimental
The sticking probability for hydrogen, S, iscalculated from the rate of the H-D exchange
reaction, which is measured with laterally
resolved mass spectrometry. A simple modelis used in order to extract S from the rate
data [1]. It is assumed that S is the same for
H2, HD and D2, and that the desorption rates
are second order in the coverages of H and
D. The apparent activation energy forhydrogen desorption, Eapp, can be obtained
from data for S as a function of temperature.

Results
With the anode reaction of the PEMFC in
mind, an investigation was carried out for anumber of transition metals, deposited as 50
Å films on Highly Ordered Pyrolytic Graphite(HOPG). The values for S and Eapp are in
reasonable agreement with literature values
obtained at high hydrogen coverage undervacuum conditions [2]. Metals which bindhydrogen strongly would be expected to havea high coverage of H, and thus to give a low
value for S. However, Ru and Rh bind H
stronger than Pt, but give larger values for S.

The fact that Pt works better than Ru and Rh
in a PEMFC may be due to Ru and Rh being
oxidized under typical operating conditions. S
was also measured with 10 ppm CO added
to the hydrogen. The influence of CO on S isstrongest for Ir and Pt. These metals show
the largest difference between the heats ofadsorption for CO and H [3]. S for Pt issignificantly more sensitive to CO than thecurrent of a PEMFC with Pt as anodecatalyst. This indicates that reactions which
consume CO are important for the resistanceto CO poisoning of a real PEMFC.
Investigations were also carried out for Ru
and Pt nano-particles produced by metal
evaporation onto sputtered HOPG. There is a
maximum in S for a particle diameter, d, ofabout 3 nm for Ru, but for Pt, S increases
with decreasing d. Eapp increases withdecreasing d for both Pt and Ru, but theeffect is more pronounced for Ru.
Presently, metal alloys such as Pt/Bi and
Pt/Ru are investigated in order to study theligand effect separately from the bi-functional
effect. So far, it seems that a surface whichcontains about equal amounts of Pt and Ru
gives an even higher value for S than pureRu, whereas no improvement in S was
obtained by adding Bi to a Pt surface.

References[1] M. Johansson, O. Lytken, I. Chorkendorff,
Topics in Catalysis 46 (2007) 175.
[2] M. Johansson, O. Lytken, I. Chorkendorff, J.
Chem. Phys. 128 (2008) 034706.
[3] M. Johansson, O. Lytken, I. Chorkendorff,
Surf. Sci. 602 (2008) 1863.

Corresponding author: Martin Johansson, email: marjo@fysik.dtu.dk, Tel. (+45) 45253191

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3rd Hydrogen & Energy Symposium

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Experimental electronic charge density of LiBD4/LiBH4
from maximum entropy method
F. Buchter1, Z. Lodziana1, A. Remhof1, Ph. Mauron1, A. Züttel1, Y. Filinchuk2, T.
Noritake3, S. Orimo4
1

Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
2

Swiss-Norwegian Beamline, ESRF, BP220, Grenoble Cedex, France.

3

Toyota Central R&D Labs., Inc., Nagakute, Aichi 480-1192, Japan.

4

Institute for Materials Research, Tohoku University, 980-8577 Sendai, Japan.

Combining neutron diffraction data and X-ray diffraction data, the experimental charge density distribution
using the maximum entropy method has been determined for LiBD4/LiBH4. This method gives afundamental information about the charge transfer and bonding nature between the different atoms within
the compound and can be directly compared to ab-initio calculations of the charge density.

Introduction
Alkali and alkali-earth complex hydrides arepromising hydrogen storage materials, but
desorb hydrogen at a high temperature andpressure level, due to either their
thermodynamical stability or a kinetic barrier.
In order to tailor the temperature/pressurelevel to suitable conditions, it is important tounderstandtheirmechanismofformation/decomposition.
Anaccurate
experimental investigation of the electronic
charge density distribution of the complex
hydrides give important information about the
charge transfer and bonding nature between
the different atoms within the compounds.

Experimental
Combining neutron diffraction data for therefinement of the structural model, andsubsequently X-ray diffraction data for the
structure factor extraction, allows thecalculation of the experimental charge
density distribution1 (see Figure 1). Due tothe limited number of extracted structure
factors, the maximum entropy method has
been used in order to give the most probablecharge density map for the set of extracted
structure factors2,3.

Results
The experimental electronic charge density
distribution is compared with the electronic
charge density distribution obtained by abinitio calculations1.

Fig. 1. Experimental charge density distribution of
LiBD4 from maximum entropy method.

References[1] F. Buchter et al. In preparation.
[2] T. Noritake et al. Journal of Alloys andcompounds, 393, 264-268, 2005.
[3] M. Sakata, M. Sato, Acta Crystallogr. A, 46,
263-270, 1990.

Corresponding author: Florian Buchter, email: florian.buchter@empa.ch, Tel. (+41) (44) 823 4082.

39

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Analysis of possible magnetic Structures in ErMn2D2
deuteride
Andrzej Budziak1), Wiesława Sikora2), Henryk Figiel2)
1)

The H. Niewodniczanski Institute of Nuclear Physics,
Radzikowskiego 152,
31-342
Krakow, Poland, 2) Faculty of Physics and Applied Computer Science AGH - University of
Science and Technology, 30, Mickiewicza av., 30-059 , Krakow, Poland
The analysis of possible
magnetic structure of ErMn2D2 deuteride is presented. Starting from themonoclinic structure C2h3 at 150 K as determined by use of synchrotron radiation, the neutron diffraction
data were analysed with the aim to find the proper magnetic structure. To solve this problem the symmetry
analysis was used to find the possible rearrangements of the Er and Mn magnetic moments accompanyinghydrogen/deuterium uptake. Possibilities of magnetic structures with hexagonal and monoclinic structures
were discussed. It appeared, that more than one propagation vector should be used suggesting weakcoupling between Mn and Er magnetic sublattices.

Introduction
In this work the attempts to fit a magnetic
structure for ErMn2D2 are presented anddiscussed. The problem appeared more
complicated than expected. The ErMn2
Laves phase type intermetallic compound
crystallizes in the C14 type structure. After
deuterization the single phase deuteride
ErMn2D2 were obtained with the hexagonal
structure P63/mmc at 298K and themonoclinic structure C2h3 at 150 K as
determined from the diffraction usingsynchrotron radiation [1].
The deuteride
orders magnetically at 205±5 K [2].

Theoretical approach
The neutron diffraction pattern taken at low
temperatures [2] contains additional lines
related both with magnetic order an orderingof deuterium. To fit the pattern using e.g.
Fullprof approach the symmetry analysis wasused to find the possible ordering ofDeuterium and the Er and Mn magnetic
moments accompanying hydrogen/deuterium
uptake. In frames of the symmetry analysis
possiblesymmetry
subgroups
andcorresponding allowed representations of theinitial D6h4 due to hydrogen/deuterium
distribution in the C14 structure were found.

For each representation the change of site
occupation, accompanying displacements ofatoms and ordering of magnetic moments
were given.

Results and discussion
The fits of the all possible ordering models(both magnetic and deuterium ordering) tothe experimental diffraction pattern [2] were
performed for the selected D6h4 subgrouprepresentations leading to C2h3 (with k = 0, 0,
0 and -1, 1, 0). The results were not fully
satisfactory. For the C2h3 as the initial groupall possible wave vectors k were taken into
consideration and we concluded that morethan one k vector should be taken todescribe the observed order. This is inagreement with independent ordering of Er
and Mn magnetic sublattices. However anordering of both lattices is visible from about
150 K.

References[1] J.P.Maehlen, et al., J. of Alloys andComp., Vol. 437, no. 1/2 (2007), 140-145[2] H. Figiel, et al., J. of Alloys and Comp., Vol.
368 (2004) 260-268

Corresponding author: W. Sikora, email: sikora@novell,ftj.agh.edu.pl Tel. (+48) (12) 6173850

40

3nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

A comparative study of the additive role in the MgH2Nb2O5 system vs. the MgH2+2LiBH4-Ti-iso system
E. Deprez1, C. López-Cartes1, M.A. Muñoz-Márquez1, O. Friedrichs1,2, J.C.
Sánchez-López1, U. Bösenberg3, C. Bonatto Minella3, M. Dornheim3, R.
Bormann3, A. Fernández1
1

Instituto de Ciencia de Materiales de Sevilla, CSIC-Univ. Sevilla, 41092 Seville, Spain
EMPA, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Hydrogen &Energy, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
3 Institut für Werkstoffforschung, GKSS Forschungszentrum, 21502 Geesthacht, Germany

2

The objective of the present work is the comparative study of the behaviour of the Nb- and Ti-based
additives respectively in the MgH2 single hydride and the MgH2+2LiBH4 reactive hydride composite. X-Ray
Diffraction (XRD), X-Ray Absorption Spectroscopy (XAS), X-Ray Photoelectron Spectroscopy (XPS) andElectron Microscopy (TEM/EELS) analysis were carried out for the milled and cycled samples in absenceor presence of the additives. It has been shown that although the evolution of the oxidation state for bothNb- and Ti-species are similar in both systems, the Nb additive is performing its activity at the surface
while the Ti active species migrate to the bulk improving the absorption/desorption kinetics; the possible
action mechanisms are discussed here.

Introduction
Single hydride (MgH2) as well as reactive
complex hydrides (RHC) (MgH2+2LiBH4) arepromising materials for hydrogen storage dueto their high storage capacities. Valuablekinetics improvements have been obtainedby using Nb2O5 [1] and Ti-isopropoxide [2]additives respectively for the single hydrides
and reactive hydride composites (RHC). It isof fundamental interest to understand theevolution and role of the additives during thedesorption/absorption
cyclesofthepresented systems. Comparative results arepresented in this work for both types of
hydride systems.

to the surface while the Ti compounds are
not detected anymore at the sample surface.
It has been shown that the Nb-based additive
is working in the single hydride system fromthe surface, opening pathways that facilitate
the diffusion of hydrogen through the
diffusion barriers. Instead, for the Ti-based
additive in the reactive hydride composite,
the active species are working in the bulk,
probably enhancing the nucleation of the
MgB2 phases during operation of the system.

Results
The XANES analysis of the XAS spectra forboth additives, Nb and Ti K-edges, shows an
irreversible oxidation change after the firstdesorption step from an average oxidation
state of 4+ to more reduced species (likely
2+).
Although the two systems look like very
similar from the XAS analysis, the XPS study
has shown strong differences (see Fig.1). In
the as-prepared samples, Nb is not present
at the surface while there is a remarkable Ti
signal. After desorption and absorption
cycles the Nb species migrate from the bulk

Fig. 1: Nb-3d and Ti-2p photoelectron spectra ofmilled and thermal treated samples respectively
for the MgH2-Nb2O5 and the MgH2+2LiBH4-Ti-iso
systems

References[1] Friedrichs et al; Acta Mater. 54 (2006) 105[2] Bösenberg et al; Acta Mater. 55 (2007) 3951

Corresponding author, Asunción Fernández, e-mail: asuncion@icmse.csic.es

41

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009Low
temperaturehydrogenMgH2/Mg(OH)2 systemdesorption

fromF. Leardini, J.R. Ares, J. Bodega, J.F. Fernández, I.J. Ferrer and C. Sánchez
Dpto. Física de Materiales, Universidad Autónoma de Madrid, 28049, Madrid, SpainAt ambient conditions magnesium hydridespontaneously transforms into magnesiumhydroxide due to the following hydrolysis
reaction [1,2]: MgH2+2H2O→Mg(OH)2+2H2(1)
The
thermaldesorption
spectraof
MgH2/Mg(OH)2 composites formed by thisreaction present a complex structure.
Besides the H2O and H2 desorption events
due to Mg(OH)2 and MgH2 decomposition,
two additional H2 desorption peaks areobserved at lower temperatures (Fig.1). This
work aims to analyze the processes whichgive place to those desorption peaks andevaluate their possible application forhydrogenproduction
atmoderate
temperaturesbyreaction
betweenmagnesium
hydrideandmagnesiumhydroxide.
To this aim, thermal decomposition of
MgH2/Mg(OH)2
composites
has
been
investigatedby
Scanning
Electron
Microscopy, Temperature Programmed X-ray
Diffraction
andThermalDesorption
Spectroscopy. In addition, experiments withdifferent
hydrogen-deuterium
isotopic
mixtures have been performed to determine
the reaction pathways.
Obtained results point out that the lowtemperature hydrogen desorption events are
related to hydride/hydroxide reactions, as
occurs in analogous systems such as the
LiH/LiOH one [3]. More specifically, these
events seem to proceed through reaction
paths similar to those proposed for thehomolytic and heterolytic dissociation of H2 in
MgO [4].
In order to enhance the amount of H2
released at low temperatures, experimentswith composites prepared by milling MgH2

powders are currently

inFig.1.
Thermaldesorption
spectraMgH2/Mg(OH)2 sample (HR=20 ºC/min).

ofand Mg(OH)2
progress.

References
[1]
[2]
[3]
[4]

J. Huot, G. Liang and R. Schulz, J. Alloys
Comp. 353 (2003) L12-L15
R.A. Varin, S. Li, A. Calka, J. Alloys Comp.
376 (2006) 222-231
J.J. Vajo, S.L. Skeith, F. Mertens and S.
Jorgersen, J. Alloys Comp. 390 (2005) 55-61
E. Knözinger, K-H Jacob and P. Hofmann, J.
Chem. Soc. Farad. Trans. 89 (1993) 11011107

Acknowledgements
We thank the Spanish Minister of Educationand Science (MEC) for financial support
under contract MAT2005-06738-C02-01.
Technical assistance of Mr. F. Moreno is also
gratefully acknowledged.

Corresponding autor: fabrice.leardini@uam.es tlf: +34 914974777

42

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Photobiological Hydrogen
Fermentation Effluent

Production

from

dark

HIdayet Argun, Fikret Kargı, İlgi K. Kapdan
Department of Environmental Engineering, Dokuz Eylül University, Buca Izmir, Türkey
Hydrogen production capabilities of different Rhodobacter species by light fermentation of darkfermentation effluent of wheat powder solution were investigated. Dark fermentation effluent
containing 2400 mgL-1 total volatile fatty acid (TVFA) and 3.6 mgL-1 NH4-N was used for biohydrogen production by light fermentation using three different Rhodobacter sphaeroides (RS)strains (RS-NRRL, RS-DSMZ and RS-RV) with an initial cell concentration of 0.2 gL-1. The
mixed culture of the three Rhodobacter strains resulted in the highest yield and specifichydrogen formation rate (SHPR) as 693 ml H2 g-1 TVFA and 12.1 ml H2 g-1biomass h-1,
respectively.

Materials and Methods
The strains were grown on their proper growth media. Initial pH and ORP of the medium was adjusted to7.45 and -150mV respectively. The inoculated bottles were placed in front of 5500 lux light illuminating
flourescent lamps at a constant temperature of 30 oC. Samples removed from the liquid phase wereanalyzed for TVFA and NH4-N. Hydrogen gas was sampled from the head space of the bottles andhydrogen concentration was determined by using a gas chromatograph (Agilent 6890). The amount of
total gas produced was determined by water displacement method. Cumulative hydrogen data werecorrelated with the Gompertz equation. Biomass concentration in the inoculum was determined by drying
the sample at 105 oC and determining the constant dry weight. The hydrogen yield and specific hydrogenproduction rate (SHPR) were used as comparison criteria.

Results
Table 1- The hydrogen yields and SHPR for different combinations of the Rhodobacter sphaeroides cultures. The-1
hydrogen yield for the dark fermentation was 1.53 mol H2 mol glucose which was added to the light fermentation yield
to obtain the total yield.

Mixed cultures

TVFAo(mgL-1)TVFAF(mgL-1)

Yield(mlH2g-1 TVFA)

RV+ NRRL
RV+DSMZ
NRRL+DSMZRV+NRRL+DSMZ

2250
1960
1970
1700

810
1410
890
1260

103.2
662.9
14.9
692.8

Total Yield SHPR, ml H2(molH2mol g-1 biomass hglucose-1) 1
1.87
19.85
3.72
11.16
1.58
1.14
3.81
12.11

Cumulative hydrogen volumes for RV+ NRRL, RV+DSMZ, NRRL+DSMZ, RV+NRRL+DSMZ were 36.5ml,
90 ml, 3.9ml, 74.8ml respectively.

Discussion
In order to obtain high cumulative hydrogen and formation rate either RV+ DSMZ or RV+NRRL mixtures
should be used. The inclusion of RV culture has improved the performance of the mixtures considerably.
Although RV + DSMZ produced the most amount of cumulative hydrogen, a combination of all three
Rhodobacter species resulted in the highest hydrogen yield and rate. This is due to different fermentation
pathways used by different cultures completing each other.
Acknowledgement: This study was supported by the Scientific and Technological Research Council ofTurkey by a Grant number TUB 105M296.

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3rd Hydrogen & Energy Symposium

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Thursday44

3rd Hydrogen & Energy Symposium

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Attempts to understand electrochemical, photochemical and biological Water splitting within the same
conceptual Framework
J. Rossmeisl and Jens K. Nørskov
Center for Atomic-scale Materials Design, Department of Physics, Technical University ofDenmark, DK-2800 Lyngby, Denmark
Electrochemical and photo-electrochemical water splitting is a key process in hydrogenproduction from sunlight, either by first using a photovoltaic cell to generate an electrostatic
potential followed by electrolysis or in an integrated process such as the Graetzel cell1. At theanode water is split and molecular oxygen evolves together with protons and electrons. At thecathode molecular hydrogen is produced by recombination of the protons and electrons. The
anode reaction is found to be associated with slow kinetics and an effective catalyst for theoxygen evolution reaction is needed. The best anode catalysts known today is RuO22
sometimes mixed with IrO23.
The water splitting and oxygen evolution process has a biological analogue in photosynthesis.
The catalytically active part of the Photo System II enzyme is a Mn-O cluster4,5. This cluster isthe result of evolution through billions of years, and it is likely to be a highly effective catalyst
system.
We make a comparison between the catalytically active sites of the inorganic and biologicalwater splitting catalysts6,7. We do that using a simple scheme developed for understanding
trends in the electrocatalytic activity8 including the water splitting reaction9. Using density
functional theory calculations we estimate the free energy of all intermediates in the reaction
and show that the inorganic and biological water splitting reactions can be described in thesame framework. We introduce the concept of the thermochemically optimal catalyst and showthat while the best known inorganic catalysts, RuO2, IrO2 are quite close to optimal; the model ofthe biological system is even closer. This finding gives hope that better inorganic
electrocatalysts can be found. It may also indicate why the Mn cluster is unique in biology.

1

M. Graetzel, Nature 414, 338 (2001)
S. Trasatti, Electrochimica Acta. 36, 225 (1991)
3
A. Marshall, M. Tsypkin, B. Børresen, G. Hagen, R. Tunold, J. New Mater. Electrochem. Syst. 7, 197(2004)
4
K.N Ferreira, T.M. Iverson, K. Maghlaoui, J. Barder and S. Iwata, Science 303, 1831 (2004)
5
B. Loll, J. Kern, W. Saenger, A. Zouni, J. Biasiadka. Nature 438, 1040 (2005)
6
J. Rossmeisl, K. Dimitrievski, P. Siegbahn, and J.K. Nørskov, J. Phys. Chem. C, 111, 18821 (2007)
7
A. Valdes, Z.W. Qu, G.J. Kroes, J. Rossmeisl, and J.K. Nørskov J. Phys. Chem. C, 112, 9872 (2008)
8
J.K. Nørskov, J. Rossmeisl, A. Logadottir, L. Lindqvist, J.R. Kitchin, T. Bligaard, and H. Jónsson, J. Phys.
Chem. B 108, 17886 (2004)
9
J. Rossmeisl, Z.W. Qu, H. Zhu, G.-J. Kroes, J.K. Nørskov. J. Electroanalytical Chem. 607, 83 (2007)
2

Corresponding author: Jens K. Nørskov, email: norskov@fysik.dtu.dk
45

rd

3 Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Powder Diffraction Studies of Light Weight Hydrogen
Storage Materials
B. David
ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxon, OX11 0QX, UK

46

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Mechanism of H-Sorption In Complex Hydrides
Andreas Züttel, Oliver Friedrichs, Andreas Borgschulte, A. Remhof
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland

Introduction
The stability of complex hydrides isinvestigated based on the enthalpy offormation of the elemental hydrides and theintermetallic compounds involved in thereaction. The equilibrium hydrogen pressure
for the absorption and desorption reaction is
calculated.

The stability of the TH4- is determined by the
localisation of the electron on the T-atom. As
a consequence the stability of the complex
hydridestrongly
dependsontheelectronegativity of the cation. However, thisapproach is only able to describe the stabilityof the forth hydrogen atom in the anion. The
stability of the neutral and “hypothetical” TH3
is also determining the equilibrium pressureof the complex hydride.
The appearance or the induced creation ofintermediate products in the hydrogen
desorption reaction is a possibility todestabilize the complex hydrides and to
facilitate the reversible hydrogen absorption.

Fig. 1. Energy diagram of metal and complex
hydrides.

Mechanism
The mechanism for the hydrogen absorption
and desorption in complex hydrides is notknown yet. In the conventional view thecomplex hydride with a general formula of
Mx+[TH4-]x (M = Li, Na, Mg, Ca…; T = Al, B, N
and x is the stoichiometry) releases H- toform MHx + x·TH3 [1,2]. The stability of the
AlH3 < BH3 < NH3, therefore, alanates
decompose into hydrogen and aluminum
while boranates tend to liberate besidehydrogen also B2H6 and the ammonium
spontaneously decomposes into NH3.
Therefore, the thermodynamics i.e. stability
and kinetics is calculated based on theintermediate products identified.

Fig. 2. Mechanism of the Li[BH4] formation.

References
[1]

[2]

Andreas Züttel, Andreas Borgschulte andShin-ichi Orimo, « Tetrahydroborates as newhydrogen storage materials », Scripta
Materialia, Volume 56, Issue 10, May 2007,
Pages 823-828
Shin-ichi Orimo, Yuko Nakamori, Jennifer R.
Eliseo, Andreas Züttel and Graig Jensen,« Complex Hydrides for Hydrogen Storage »,Chemical Reviews, October 2007, Volume
107, Number 10, 4111-4132

Corresponding author: Andreas Züttel, email: andreas.zuettel@empa.ch, Tel. (+41) (44) 823 4038

47

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Hydrogen production by alkaline electrolysis: is there a
way to increase its efficiency?
Valentina Zakaznova-Herzog and Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
In the presentation, we review the current state of technology of hydrogen production by alkaline
electrolysis. High pressure alkaline electrolyser’s efficiency depends significantly on the ion-conductivityof membrane separating oxygen and hydrogen. Low gas penetration and high ion conductivity are twomain conflicting objectives. Low gas penetration results in high gas purity while high ion conductivity
improves the overall efficiency of the electrolysis. Currently used membranes are made from asbestos,which are not only prohibited by recent health regulations, but also require high energy consumption. Our
approach is to improve the ion conductivity of asbestos membranes while keeping its excellent gas
tightness. The first research direction for boosting the efficiency of alkaline electrolysis is the investigationof surface contributions on the fresh and reacted asbestos (Mg3Si2O5(OH)4) and other silicate minerals.

Current
state-of-technology
alkaline electrolysis

in

Production of hydrogen using alkaline
electrolysis was established over 50 years
ago. Due to the high energy consumption forthe hydrogen production via alkaline
electrolysis only 4% of world hydrogenproduction is by means of electrolysis (U.S.
Department of energy). Strong fluctuations offuel fossil prices, facing the starting of “oilpeak” and climate changes made alkaline
electrolysis suddenly more attractive thanhydrogen production from fossil fuels. A
review of an existing literature on the alkaline
electrolysis improvements will be presented
and evaluated. [e.g., 1,2].
However,currently available high pressure industrial
alkaline electrolysers are based on thetechnology available of 1950ties. Possible
scenarios on efficiency improvements will be
discussed.

consumption of an electrolyser. Therefore, amembrane is the central issue in theelectrolysis efficiency. Surprisingly, thesurface contributions on the new and reacted
asbestos and reaction mechanisms are notwell understood and researched. The
following questions are still unresolved:
Which chemical interactions occur on themembranesurface?
How
ions
are
transported over membrane? How to predictthe long-term stability of material? Whichmodelsareavailable?
Systematic
experimental investigation of surfaces ofmembranes for alkaline electrolysis will be
performed with the objective of collecting
experimental data for developing a model topredict ion conductance and related physicalchemical properties over time. This project iscombined with the development of new
membranes integrated in the alkaline
electrolysis cells [3].

Stated problems and outlook

References

One of the main components of anelectrolyser is the membrane between
cathode and anode separating hydrogen andoxygen gases; it effect strongly energy

[1]
[2]
[3]

Helmet et al., (1984) CEC report
Ghosh et. al. Solar Energy 75 (2003) 469–
478
M. Gorbar et al., Poster, this conference

Corresponding author: V. Zakaznova-Herzog, email: valentina.herzog@empa.ch, Tel. (+41) (44) 823 4352

48

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

La0.6Sr0.4Co0.2Fe0.8O3-δ Microstructures obtained byelectrostatic Spray Deposition for IT-SOFC
Daniel Marinha, Elisabeth Djurado
Laboratoire d’Electrochimie et de Physico-Chimie des Matériaux et des Interfaces
Grenoble Institute of Technology/UJF/CNRS (UMR5631)
The deposition of La0.6Sr0.4Co0.2Fe0.8O3-δ films on Ce0.9Gd0.101.95 by Electrostatic Spray Deposition ispresented. The influence of temperature, nozzle-to-substrate distance, and flow rate parameters on film
morphology was evaluated. We report the formation of dense, porous, reticulated and nanostructured
microstructures with great interest as cathode layers for IT-SOFC and discuss the formation mechanism.
Films were characterized by scanning electron microscopy and XRD was performed on samples annealed
at different temperatures.

Introduction
Future development of SOFC technology isstrongly dependent on lowering the operation
temperature down to an intermediate range,
consequently leading to an improvement of
the cost/benefit ratio. Still, current SOFC
materials yield unsatisfactory performances
under such conditions, largely due to anincrease in electrode polarization resistanceand of ohmic losses in the electrolyte, which
drastically affect the power output of theensemble. On the cathode side, whilechanging the material from a purely
electronic to a mixed ionic electronic
conductor leads to an increase in theefficiency of electrochemical reactions, muchcan be also done in terms of microstructuraldesign[1, 2]. Therefore, a systematic study
correlating the microstructural aspects of thecathode film and respective electrochemical
performance is highly desirable. From a
microstructural standpoint, the optimal
cathodic layer microstructure should haveenough porosity to allow gaseous permeation
while guaranteeing a percolative pathway forcharge transport, and provide a high volumic
density of triple phase boundary (TPB)
regions contributing to current generation.
The focus of our preliminary work is to design
such microstructures.

Experimental
In our investigation we have used
Electrostatic
Spray
Deposition(ESD)
technique to deposit La0.6Sr0.4Co0.2Fe0.8O3-δ
(LSCF) films on Ce0.9Gd0.101.95 (CGO)
substrates, and evaluate the influence of film
processing
parametersonresultingmicrostructures. Nozzle-to-substrate distance(15, 30, 45, 48 and 53 mm), solution flow rate
(0.34, 0.67 and 1.5 mL/h), and substratetemperature (300, 350, 400 and 450 ºC)
were varied and resulting films werecharacterized by SEM/EDS and XRD.

Results
By varying the ESD deposition conditions, it
was possible to obtain dense, reticulated,porous and nanostructured LSCF film
microstructures. Film crystallinity wasconfirmed by XRD and the correlation
between deposition parameters and resulting
morphology discussed in detail.

References[1] F. Tietz, et al.; Solid State Ionics 27-32(2008) 179[2] A. S. Martinez, et al.; Electrochem. Acta
10 (2008) 53

Corresponding author: Elisabeth Djurado, email: Elisabeth.Djurado@lepmi.inpg.fr, Tel. (+33) (47) 682
6684 (+41) (44) 823 4153

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3rd Hydrogen & Energy Symposium

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High Temperatur Steam electrolysis by SOEC
Technology
Ulrich F. Vogt1, Daniel Wiedenmann1, Anne Hauch2, Mogens Mogensen2,
Andreas Züttel1
1

Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
2
National Laboratory for Sustainable Energy, Risø, Technical University of Denmark, 4000
Roskilde, Denmark
The wide variety of energy sources, including renewables, which can be used to produce hydrogen, makes
it more and more attractive as an energy carrier. Solid Oxide Fuel Cells (SOFC) used in electrolysis mode,
called Solid Oxide Electrolysis Cells (SOEC), have a great potential for cost efficient and economical
production of hydrogen due to steam electrolysis by applying an external voltage. The electricity demandfor electrolysis can be significantly reduced if the formation of hydrogen takes place at high temperatures(600-950°C). At these elevated temperatures, the required electrical energy can be partially substituted bythermal energy as the water splitting process is increasingly endothermic with rising temperature. If
additional heat is available from sources like solar, nuclear, or other industrial waste heat, this will allow
further reduction of the electrical energy demand.

Introduction
The SOEC technology has very sophisticatedrequirements to the cell materials due to thehightemperature
and
high
steam
concentration on the electrodes.
In the EU project Hi2H2 EMPA has
synthesised and characterised several
perovskite powders for new cell materials
which has been set up by the project
partners.

Experimental
For new cell materials and protective layers,
Perovskite powders have been synthesizes
by the solid state- and pyrolysis method.
The spinell composition MnCo2O4 wasproduced by the solid state technology forprotective coatings against Cr diffusion
processes
fromthe
Cr-containing
interconnector. For the O2 electrodes,
SrNbTiO3 and LaSrCoOr have beendeveloped and characterized by several
methods.

Results
The uniqueness of the concept is to perform
water electrolysis at a rather hightemperatures between 600 and 950°C.
Outstanding performances were achieved at
950°C, using electrode supported SOECs
made at Risoe – DTU. Here, steam
electrolysis was operated at a current densityof -3.6 A/cm2 and a cell voltage of only 1.48
V. These current densities were obtained atvery high electrical efficiencies which would
correspond to a production rate of hydrogenof 1.34 kgm-²h-1.

References[1] U.F. Vogt, J. Sfeir, J. Richter, C. Soltmann, P.
Holtappels; Pure Appl. Chem., Vol. 80, No. 11, pp.
2543–2552, 2008.
[2] A. Hauch, S. D. Ebbesen, S. H. Jensen, M.
Mogensen, J. Mater.Chem., 2008, 18, 2331-2340[3] S. H. Jensen, P. H. Larsen, M. Mogens, Intern,
Journal of Hydrogen Energy 32 (2007) 3253-3257
2[4] Hi H2 project report 503765, 2007
[5] M. Ni, K.H.Leung, D.Y.Leung, Int. J. of Hydrogen
Energy 33 ( 2008) 2337-2354

Corresponding author: Ulrich Vogt, email: Ulrich.vogt@empa.ch Tel. (+41) (44) 823 4160

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3rd Hydrogen & Energy Symposium

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FIB/TEM and EPMA as complementary Techniques forthe investigation of SOEC and SOFC
Daniel Wiedenmann1, Christian Soltmann, Mogens Mogensen2, Ulrich Vogt1
1

Laboratory Hydrogen & Energy, Empa, Swiss Federal Laboratories for Material Testing and Research
National Laboratory for Sustainable Energy, Risø, Technical University of Denmark, 4000 Roskilde,
Denmark

2

An electrolysis cell is an electrochemical device, which can directly convert electrical energy into
chemical energy. High temperature steam electrolysis by solid-oxide electrolyser cells (SOEC)
is a way with great potential to transform renewable energy from non-fossil sources with highefficiency and to use hydrogen as an energy carrier.

Introduction
SOEC are based on composites of advanced
ceramic materials like e.g.: yttria stabilized
zirconia(YSZ-electrolyte),
lanthanumstrontium
manganate(LSMoxygen
electrode), Ni-YSZ cermet (fuel electrode)and steal alloys (interconnector). Due to thehigh operating temperatures of SOEC (600900°C), structural and chemical degradationof the cells occur, caused by element
diffusionandnon-uniform
expansioncoefficients of the composite parts.
Additionally, external poisoning from the cellsealing and the interconnector is a common
phenomenon. This work focuses on thecharacterization of changes in aged SOEC
by electron-microscopical methods.

Experimental
Representative examination and post
mortem analysis of SOFCs and electrolyser
cells (SOECs) often requires the chemicaland structural characterization on the
microscopic and nanoscopic level. A
combination of scanning electron microscopy
with electron-probe microanalysis (EPMA),
the focused ion-beam (FIB) technique andtransmission electron microscopy (TEM) can
help to examine processed samples on aquantitative level over a large sample areaon the one hand while allowing tocharacterize structural and chemical changesof selected sample details on the nanoscale.

While the EPMA technique allows forquantitative chemical analysis and structural
examination on the microscopic level, TEM ofsuitably prepared samples enables to image
the nanostructure and to characterize thechemical composition at the same time.

Results
Here we present results of the structural andchemical characterization of changes indifferent aged electrolyser cells, which aimed
at examining metal diffusion and thedeposition of impurities in these cells. Si
impurities were observed to be enriched at
the triple phase boundaries and between Ni
and YSZ particles.

References[1] R. Langford, in: N. Yao (ed.), Focused ion
beam systems: Basics and applications 2007,
Cambridge University Press, 215-249.
[2] J. Orloff et al., Kluwer Academic/Plenum
Publishers 2003, 205-286.
[3] M.W. Phaneuf, Springer Science + BusinessMedia 2005, 143-172.
th[4] A. Hagen et al., in: M. Mogens (ed.), 6
European Solid Oxide Fuel Cell Forum
Proceedings, Switzerland 2004, 930-939.
[5] A. Hauch et al., Soc. 2006, 153 A1741-A1747.
[6] A. Hauch, Solid Oxide Electrolysis Cells –Performance and Durability, Ph.D. thesis,
Technical University of Denmark 2007.
[7] M. Ni et al., International Journal of Hydrogen
Energy 33 (2008), 2337-2354.

Corresponding author: Daniel Wiedenmann, email: daniel.wiedenmann@empa.ch, Tel.(+41)(44) 823 4862

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3rd Hydrogen & Energy Symposium

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Impact of the Surface Oxidation of LiBH4 on the H2Desortpition Processes
Shunsuke Kato, Andreas Borgschulte, Michael Bielmann, Arndt Remhof,
Valentina Zakaznova-Herzog, Flavio Pendolino, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The surfaces of LiBH4 were intentionally modified by exposing to different amounts of O2. With respect tothe hydrogen desorption processes, the induced surface changes of the samples were systematicallystudied by means of Temperature Programmed Desorption spectroscopy (TPD) and X-ray Photoelectron
Spectroscopy (XPS).

Introduction
Under practical conditions, the surface
contamination of hydrogen storage materials
has to be taken into account [1]. Therefore, athorough study of the oxidation of hydrides
surfaces under defined conditions is
mandatory in order to clarify the hydrogen
sorption mechanisms. This work aimed atinvestigating the surface oxidation of LiBH4
with respect to the hydrogen desorption
kinetics.

Experimental
The TPD measurements were carried out inthe pressure range from 10-9 mbar to 10-5
mbar and in the temperature range up to 873
K. The desorbed products were measured byusing a mass spectrometer (QMS). In the
study of the surface oxidation by XPS, thesample was prepared inside Ar glove box (O2< 5 ppm, H2O < 0.1 ppm) connected to thespectrometer and directly transferred. The
clean surface of LiBH4 was successfully
prepared by a mechanical process under
UHV, without any destructive process suchas Ar ion sputtering. Subsequently, thesample surface was exposed to O2 (99.999%) at the pressures ranging from 10-10 up to
10-4 mbar and at the temperature of 313 K.
The XPS spectra were collected by using
non-monochromatic X-ray twin anodes (MgKα: 1253.6 eV, Al Kα: 1486.6 eV).

Results
The surface modification by O2 significantly
reduces the desorption of borane products
and increases the hydrogen desorption rate.
The oxidation study by XPS confirmed thatthe surface oxidation induces a Li-enrichedsurface on LiBH4 and changes the chemical
state of B. The oxidation of B on the surfaceof LiBH4 may play an important role in the
improvement of the hydrogen desorption
properties.

References[1]

A. Borgschlute, M. Bielmann, A. Züttel,
G.Barkhordarian, M. Dornheim, R. Bormann,
Applied Surface Science 254 (2008) 2377.

Corresponding author: Shunsuke Kato, email: shunsuke.kato@empa.ch, Tel. (+41) (44) 823 4327

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A theoretical Study of H2 reacting on Ti/Al(100) surfaces
J.-C. Chen1, J. C. Juanes-Marcos1, A. Al-Halabi1, R. A. Olsen1;2, and G.-J.
Kroes1
1

Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University,

P.O. Box 9502, 2300 RA Leiden, The Netherlands
2

Akershus University College, P.O. Box 423, N-2001 Lillestrom, Norway

Using DFT method, we study H2 dissociation on Ti/Al(100) alloy surfaces, modeled by different Ti
coverages varying from 1/4 to 1 monolayer. The most realistic model promoting H2 dissociation is found tobe the (100) surface of Al covered by 1 monolayer of Ti in a c(2x2) structure, with Ti atoms in the first andthird layers. This model has a late barrier of only 0.23 eV height, and a deep molecular chemisorption wellof 0.45 eV depth in front of the barrier in the reaction path. From the view points of molecular orbital
theory, the barrier-less approach to the molecular chemisorption well is mainly explained by an occupied
virtual attraction between the H2 σg and Ti 3dz2 orbitals. The barrier separating the molecularchemisorption well and the dissociated state can be understood as resulting from a competition between
increasing overlap of the H2 σu and Ti 3dxz orbitals and decreasing overlap of the H2 σg and Ti 3dz2 orbitals.

Introduction
Motivated by this discrepancy between the Ticoverage promoting H2 dissociation [1], we
consider two questions. First, what are the bestslab models for representing (100) type alloy
surfaces for higher Ti coverages from 1/2 to 1
ML. Second, what are the minimum barrierheights for H2 dissociation on the surfaces?

Methodology
The DFT code DACAPO [1] is used to study H2dissociation on this slab models, with employing
the PW91 functional [2]. A six-dimension
potential energy surface (PES) was built by
GROW [3] method. Both dynamics quasiclassical trajectories and quantum timedependent wave packet are conducted on the
PES.

Results and discussions
Ti atoms prefer to be in the second layer of thesurface at low Ti coverage, or in the first andthird layer with a c(2x2) pattern at 1 ML
coverage. Fig 1 shows the reaction path of H2
dissociation on (100) surfaces of pure Al and ½
ML Ti (a), 1 ML in first and third layers (b), ¼
and 1 ML in first layer (c) surfaces.
Using the best model (b), we build the sixdimension PES. The well in the PES could
enhance the reaction probabilities in our
preliminary quantum dynamics for 2D, 3D and
4D PES by resonance in low range.

Fig. 1.Reaction path of Hs dissociation on
Ti/Al(100) surface..

References[1] DACAPO,
https://wiki.fysik.dtu.dk/dacapo/Dacapo.
[2] Perdew, et al; Phys.Rev. B 46 (1992) 6671.
[3] Collins; Theor. Chem. Acc.108 (2002) 313.

Corresponding author: Jian-Cheng Chen; email: jcheng@chem.leidenuniv.nl Tel: +31 71 527 4533.

53

3nd Hydrogen & Energy Symposium

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Surface analysis and oxidation state in the Reactive
Hydride Composite 2LiBH4+ MgH2+Ti-iso.
E. Deprez1, T.C. Rojas1, M.A. Muñoz-Márquez1, C. López-Cartés1, A. Fernández1, C.
Prestipino2, F.J. Palomares3, C. Bonatto4, U. Bösenberg4, M. Dornheim4, R. Bormann4
1

Instituto de Ciencia de Materiales de Sevilla, CSIC-Univ. Sevilla, Av. Américo Vespucio 49,
41092 Seville, Spain
2
ESRF, 38043 Grenoble Cedex, France
3
Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
4
Institut für Werkstoffforschung, GKSS Forschungszentrum, 21502 Geesthacht, Germany
The composite system 2LiBH4+MgH2 with Ti-isopropoxide as additive is the subject of the present study. In
particular, this work investigates the oxidation state of Titanium in the composite system 2LiBH4+MgH2 bymeans of X-ray Absorption Spectroscopy (XAS) as well as the electronic state of the elements at the nearsurface by X-ray Photoelectron Spectroscopy (XPS). Samples milled and cycled in absence or presence of
the Ti-iso additive were analysed. It was found that the active Ti species migrate from the surface to thesample bulk in the first desorption while a reduction form the 4+ to the 2+ oxidation state is also observed.
The more than probable formation of Ti-B active species is discussed.

Introduction
The Reactive Complex Hydrides are well
suited material for hydrogen storage due totheir high storage capacities [1]. Especiallythecomposite
system2LiBH4+MgH2
presents a great potential with 10 wt %hydrogen content [2]. However, thiscomposite system suffers from slowhydrogen sorption kinetics which makes its
eventual application as a hydrogen storage
material difficult [3]. To improve the kinetics,
additives such as the organometallic
Titanium isopropoxide compound wereadded providing very interesting results.
Currently, it is still not clear how the additive
interacts with the different compounds. Some
new results are presented in this work.

Titanium after the first desorption step
shifting from the oxidation state 4+ to a more
reduced state (likely Ti 2+) (see Fig.1).
All the elements present in the composite
materials were detected by XPS. The spectra
also show that after desorption andabsorption cycles Titanium is no more
detected at the surface. The possible
formation of Ti-B species is proposed as
active species enhancing the nucleation of
the MgB2 phase in the composite bulk.

Experimental
The XAS samples were prepared by mixing
BN with a determined quantity of the material
containing 10 %mol of Ti-iso. and analysed
at BM29 of the ESRF, Grenoble (France).
The XPS samples were analysed without air
exposure using an Aluminium cathode X-ray
source at the Materials Science Institute in
Madrid (Spain).

Results

Fig. 1: Ti-K edge XANES spectra of milled and 1st
step desorbed material with titanium metal andoxide references.

References[1] Dornheim et al; Scripta Mater. 56 (2007) 841[2] Vajo et al; J. Phys. Chem. B 109 (2005), 3719
[3] Bösenberg et al; Acta Mater. 55 (2007) 3951

The XANES analysis of the XAS spectra
shows an irreversible oxidation change of theCorresponding author: Emilie Deprez, email: emilie.deprez@icmse.csic.es
54

3rd Hydrogen & Energy Symposium

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Study of Hydrogen Storage Haucke Compounds:
electronic and elastic Properties
Jean-Claude Crivello1, Michèle Gupta2, Michel Latroche1
1Chimie Métallurgique des Terres Rares - ICMPE-UMR7182, CNRS - 2-8 rue H. Dunant, 94320
Thiais - France
2
TPCHO, EA 3547, Université Paris Sud-XI, Orsay, FranceThis work is a part of a complete and systematic study of the substituted Haucke phase AB5. The effect of
substituting elements on electronic properties has been studied using ab initio band structure calculations
for the ANi5 (A=La, Y, Ca) and LaNi5-xMx compounds, where M is an element of the type s-p (Al, Si, Ge,
Sn), of type s (Cu), or a transition metal (Mn, Fe, Co). The corresponding hydrides are presented. We
discuss the trends observed in the electronic structure and the factors that control the stability of theintermetallic and their corresponding hydrides. The features of the electronic properties are discussed inrelation with several experimental data and hydrogen absorption properties of these materials.

Introduction
For Haucke compounds, as well as in mostH-absorbing transition metals, the hydrogen
absorption is accompanied by a large volume
increase, the compressibility of the matrix is
expected to play an important role. The
elastic energy spent in the lattice expansion
and the energy gained from the chemical
metal-hydrogen interaction are indeed theantagonist key factors that control thestability of the hydrides. While the latter is ofpure electronic origin, the former involves
electronic as well as lattice properties.
In this work, we present the results of abinitio band structure calculations for several
substituted AB5 compounds and theircorresponding hydrides.

analyzed. These results made it possible toidentify the factors which control the stabilityof the hydrides.
The calculated bulk moduli of several
compounds are presented. These results arein satisfactory agreement with available
experimental data. They are used, in
conjunction with electronic features such as
band filling and Fermi energy characteristics,
to discuss the relationship between
compressibilities, electronic structure and Habsorption properties.

Computational method
The electronic structure calculations havebeen performed using the local density
approximation of the density functional theory
within the linear muffin-tin orbitals method
and the atomic sphere approximation.

Fig. 1. Experimental values of the plateaupressures versus the calculated bulk moduli.

Results

References

The effect of substitution elements onelectronic properties has been studied. Whiledissociating the structural effects, the role ofthe chemical interaction with hydrogen was[1] Crivello et al; J. Alloys Compd. 356 (2003) 151[2] Crivello et al; J. Alloys Compd. 404 (2005) 565

Corresponding author: J.-C. Crivello, email: crivello@icmpe.cnrs.fr, Tel. (+33) 1 49 78 11 74

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3rd Hydrogen & Energy Symposium

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Kinetics of Hydrogen sorption and desorption in ECAPprocessed Mg alloy ZK60
Maciej Krystiana b, Bernhard Minglera, Gerhard Krexnera, Michael ZehetbaueraaUniversity of Vienna, Faculty of Physics, Boltzmanng. 5, A-1090 Wien, Austria
Austrian Research Centers GmbH – ARC, Powder Technology Center, A-2444 Seibersdorf,
Austriab

ZK60 – a promising Mg-based alloy for hydrogen storage – was nanostructured by Equal Channel Angular
Pressing (ECAP). Afterwards kinetics of hydrogen sorption and desorption was investigated in a new
designed hydrogen charging Sieverts' apparatus in the temperature range of 200–350°C. Additionally thePressure-Composition-Temperature (PCT) diagram of this alloy was expanded by 4 new plateaus at low
temperatures. Moreover, the hydrogenation behaviour was compared to that of commercially available
nano-Mg powder with catalysts for hydrogen storage made by High Energy Ball Milling (HEBM).

Introduction
The direct kinetics of hydrogen sorption anddesorption of ECAP processed ZK60 as apossible low-cost material for on-boardhydrogen storage [1] is presented. The
hydrogen properties of ZK60 are compared
to a commercial hydrogen storage material.

However, 5 wt.% can be reached within 1 h
and hydrogen desorption from ECAP
processed ZK60 takes 12 min, which,although still slower than that of ball milled
Mg (6 min; s. fig 1), is sufficiently fast formobile applications. Moreover, the storage
capacity of ZK60 (6.6 wt.%) is slightly higher
than that of Mg with catalysts (6.2 wt.%).

Experimental
Samples of 20 mm in diameter and 90 mm
length were machined from a cast billet of
ZK60 alloy (5 wt.% Zn; 0.8 wt.% Zr) anddeformed by ECAP (four passes; route BC) attemperatures between 300°C and RT.
Hydrogenation experiments were carried out
in a newly-designed, portable, hydrogencharging Sieverts' apparatus [2]. The
ECAPed material was comminuted tosamples of ~400 mg in weight, charged withH2 (5.0 purity) at 1.5 MPa pressure anddischarged into an evacuated volume atconstant temperature.

Results
During ECAP the initial cast microstructure of
15 μm was substantially refined down to 400
nm. Full hydrogenation of ECAP processed
ZK60 takes 24 h time which is rather sluggish
compared to only 10 min in of ball milled Mg.

Fig. 1. Kinetics of hydrogen desorption in ZK60
(ECAP) and Mg (HEBM).

Furthermore, four new plateaus in PCT
diagram of ZK60 at 200°C, 220°C, 240°C
and 260°C could be estimated.

References[1] Skripnyuk, et al; Acta Mater. 52 (2004) 405[2] Krystian, to be publ. in Meas. Sci. Technol.

Corresponding author: Maciej Krystian, email: maciej.krystian@univie.ac.at, maciej.krystian@arcs.ac.at,Tel. University of Vienna: (+43) (01) 4277 51382; Austrian Research Centers: (+43) (0) 50550 3272

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The Global Hydrogen Market
Stefan Schlag1, Bala Suresh2, Masahiro Yoneyama3
SRI-Consulting (Access Intelligence International LLC),
1

Alfred Escher-Strasse 34, 8002, Zürich, Switzerland, 2 4300 Bohannon Drive Suite 200, Menlo
Park, CA 94025, USA, 3 Takeda Honcho Building, 2-1-7 Nihonbashi Honcho, Chuoku, Tokyo
103-0023, Japan.
Independent of the use of hydrogen as an energy carrier of the future, there is an existing globalhydrogen market of about 50 million metric tons annually. This hydrogen is to a large extent
consumed in the chemical sector (production of ammonia, methanol and in refineries). Nearly
96% of all hydrogen is derived from fossil fuels, with natural gas being by far the most frequently
used with an estimated 49%, followed by liquid hydrocarbons at 29%, 18% from coal and about
4% from electrolysis and other by-product sources of hydrogen. The size of the current market
will be compared to the size of a potential future market with hydrogen serving as an energy
carrier in transportation. The question will be raised, to what extent the existing market could
satisfy the demand of a growing "hydrogen economy" in an intermediate phase and in the longterm.

Introduction
The global hydrogen market will bepresented in terms of production capacities,
actual production and consumption byregion, as well as by application segment.
The current hydrogen market will becompared to a potential future hydrogenmarket that would include the massive use ofhydrogen as an energy carrier fortransportation.

Current Hydrogen Market
About 50 million metric tons of hydrogen arebeing produced worldwide per year and aremainly consumed in the chemical andpetrochemical industry. Refineries, theproduction of ammonia and methanol are themain consuming areas of hydrogen. Asia,
North America and Europe are the regions
where most of the hydrogen is being
consumed. Nearly 96% of all hydrogen isderived from fossil fuels, with natural gas

being by far the most frequently used with anestimated49%,
followedbyliquidhydrocarbons at 29%, 18% from coal andabout 4% from electrolysis and other byproduct sources of hydrogen.

Potential Future Hydrogen Market
The additional demand of a future hydrogenmarket is estimated, with hydrogen being
widely used as an energy carrier intransportation. Size of the additional market
is compared with the current market size. It
will be discussed to what extent the current
market could supply hydrogen into the newmarkets in an intermediate phase or in thelong term.

Reference[1] Schlag et al; CEH Report "Hydrogen"(743.5000 A, October 2007), SRI Consulting.

Corresponding author: Stefan Schlag, email: sschlag@sric.ch, Tel. (+41) (44) 283 6345

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Friday58

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Diffraction Studies of Complex Hydrides
Bjørn C. Hauback
Physics Department, Institute for Energy Technology (IFE), P. O. Box 40; NO-2027 Kjeller,
NorwayPowder neutron and X-ray diffraction are crucial methods both for accurate crystal structure
determinations and for the clarification of desorption and absorption processes in complex hydrides.
Synchrotron X-ray diffraction is in particular important for complicated structures and for in-situ
experiments. Diffraction studies of hydrides based on Al, B, Mg and N will be presented.

Introduction
In order to understand the properties ofmaterials and also to be able to determine
new compounds, detailed knowledge about
the position of the atoms is of major
importance. Neutron diffraction is a uniquetool for studies of hydrogen/deuterium inmetal hydrides. For studies of complex
structures and samples containing different
phases, the combination of powder neutron
diffraction (PND) and X-rays diffraction (PXD)
For complicated structural features and insitu experiments, the use of synchrotron
radiation X-rays (SR-PXD) is important.

combination of SR-PXD and PND is inparticular important. One example is therecent determination of the intermediatephase CaB2H2 observed during thedecomposition of Ca(BH4)2 (Fig. 1).

Experimental
Our starting materials are prepared both by
wet-chemistry methods (FZK, Germany) andby ball-milling (IFE) at different conditions: in
Ar, reactive milling with maximum 150 bar in
H2 and at liquid nitrogen temperature(cryomilling). The PND experiments are
performed with the PUS diffractometer at the
JEEP II reactor at IFE and the SR-PXD
experiments at the Swiss-Norwegian Beamlines (SNBL) at ESRF, both with the highresolution setup and the MAR image platesystem for in-situ experiments. SR-PXD
experiments are also combined with Raman
spectroscopy.

Results
Selected recent structural detailed structural
studies and in-situ desorption diffraction
experiments are presented. The materials
are novel hydrides based on boron,
aluminium, magnesium and nitrogen. The

Fig. 1. The structure model of the intermediatephase CaB2H2.

Acknowledgements
The co-workers in the group at IFE andcollaborators at FZK, EMPA and GKSS are
acknowledged. Financial support from
Research Council of Norway and European
Commission FP6 and FP7 programs.

Corresponding author: Bjørn C. Hauback, email: bjorn.hauback@ife.no, Tel. (+47) 63 80 60 78

593rd Hydrogen & Energy Symposium

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PEM Fuel Cells at elevated TemperatureJens Oluf Jensen, Qingfeng Li, Chao Pan, Niels J. Bjerrum
Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs.
Lyngby, Denmark
Proton exchange membrane fuel cells (PEMFC) are traditionally operated at temperatures below 100ºC as
dictated by the proton conducting membrane that serves as the electrolyte. The low working temperature
is a strong advantage when it comes to start-up time and choice of construction materials, but there are anumber of disadvantages relating to the low temperature that justifies the search for alternative materials,
especially membranes, that allow for a higher working temperature. During recent years such hightemperature PEM fuel cells have been developed, and this paper will present the technology, review
advantages and drawbacks, and try to give the state of art today.

Introduction
The advantages of a higher working
temperature of a PEMFC are (1) the absenceof liquid water, (2) Higher tolerance togaseous impurities like CO, (3) higher valueof excess heat and (4) easier cooling. All thiscan result in simpler system architecture andpossibly lower cost. The reason why aconventional
PEMFC
islimitedtotemperatures below 100ºC is that themembrane electrolyte depends on a highwater content in order to maintain its proton
conductivity. Water acts as a proton shuttle.
Systems with higher working temperatures
must either be pressurized dramatically or
alternative proton conduction mechanisms
must be found.

High temperature PEMFC
Many different approaches have been andare being tried for high temperatures
membranes [1], but so far the mostsuccessful one is basically to replace waterby another shuttle molecule which is lessvolatile. A major breakthrough was when
Wainright et al. [2] presented the idea of
dopingatemperature
resistantpolybenzimidazole (PBI) membrane withphosphoric acid. Shortly after, our group
continued the early effort and today PBI and
HT-PEMFC is a fast growing research field,
see Fig. 1. [3, 4] .

The applications aimed at today are:combined heat and power generation fromreformat natural gas without CO purification,
automotive propulsion, UPS and auxiliary
power systems, or for integration withmedium temperature metal hydrides [5, 6].

Fig. 1. Cumulated number of PBI and fuelcell publications (Web of Sci., Nov. 4, 2008).

References[1] Q. Li et al. Chem. Mater. 15 (2003) 4896.
[2] J. S. Wainright et al. J. Electrochem. Soc. 142(1995) L121.
[3] Q. Li et al. Fuel Cells 4 (2004) 147.
[4] Q. Li et al. Accepted review, Prog. Polymer
Sci. (2008).
[5] J. O. Jensen et al. Int. J. Hydrogen Energy 32(2007) 1567.
[6] J. O. Jensen et al. Alloys Comp. 404-406(2005) 653.

Corresponding author: Jens Oluf Jensen, email: joj@kemi.dtu.dk, Tel. +45 45 25 23 1460

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

High-Pressure and -Temperature DSC (Differential
Scanning Calorimeter) for Combined pcT (pressure,concentration, Temperature) Measurements of Hydrides
Ph. Mauron1, V. Bissig2, M. Bielmann1, A. Remhof1, A. Züttel1
Empa Materials Science and Technology, 1Section Hydrogen & Energy, 2Section of Joining andInterface Technology, CH-8600 Dübendorf, Switzerland
The design and construction of a high-pressure (200 bar) and high-temperature (600°C) heat-flow Differential Scanning Calorimeter (DSC) for combined measurements with a pcT (pressure, concentration andtemperature) system in order to investigate the hydrogenation and dehydrogenation reactions of metal
hydrides in a hydrogen atmosphere is presented. Because of the high thermal conductivity of hydrogen
only the sample and reference cell are under hydrogen pressure and the rest of the system is in air underatmospheric pressure. The DSC is designed in such a way that the internal empty volume of the sample
and reference cell is as low as possible in order to be able to make precise combined pcT measurements.
As an example the enthalpy of the hydrogenation and dehydrogenation reaction of LaNi5 is determined
during pcT measurements.

Introduction
In view of an application of hydrides ashydrogen storage medium in mobile applications the knowledge of their thermodynamic
properties is crucial in order to have a tankthat can be operated at moderate pressure
and temperature conditions [1]. A high pressure DSC in combination with a pcT system
is an ideal tool to investigate the de- andrehydrogenation enthalpies of metal hydrides

Combined pcT and DSC measurements of
LaNi5 at 60°C were made at different hydrogen flow rates. In Fig. 1 the measurement
made at a flow of 50 sccm is shown.
As a function of the hydrogen flow rate theintegrated ab- and desorption enthalpy of
LaNi5H6 is almost constant and the extrapolation to zero flow corresponding to the equilibrium are consistent with measurements
given in the literature [3].

Instrumental / Experimental
The DSC presented is of the heat-flow type.
The furnace, sample and reference temperatures are measured with Pt 100 sensors.
The upper temperature limit of the DSC is
600°C defined by the melting range of theIncusil-ABA used for joining the Pt 100 sensors. The pressure is limited by the wall
thickness of the sample and reference holder
only (0.5 mm for 170 bar and 1 mm for 420
bar at room temperature).
The pcT-system used in combination with the
DSC is a dynamic measurement system [2].

Results
The DSC was calibrated with In, Zn and anelectrical resistance for different heating
rates, powers and hydrogen pressures.

Fig. 1. Combined pcT and DSC measurement of
LaNi5H6 at 60°C and a hydrogen flow of 50 sccm.

References[1] L. Schlapbach et al., Nature 414, 23 (2001).
[2] M. Bielmann et al., sub. to Rev. Sci. Instr.
[3] W. N. Hubbard et al., J. Chem. Thermodynamics 15, 785 (1983).

Corresponding author: Philippe Mauron, email: philippe.mauron@empa.ch, Tel. (+41) (44) 823 4099

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New Tools for the Characterisation of Hydrogen
Storage Materials.
Emmanuel Wirth1, Andre Levchenko2, Karl Gross2
1: Setaram Instrumentation, 7, Rue de l'Oratoire -69300 Caluire - France

2: Hy-Energy LLC/Setaram Inc., 8340 Central Ave, Newark, CA 94560, U.S.A.

In the recent years, the solid hydrogen storage research has experienced a wide development andpromising new materials candidates such as complex hydrides, high surface areas materials, and hybrid
systems are now focusing a lot of interest. In parallel the characterisation for both evaluating the hydrogen
sorption properties and understanding of the mechanism of hydrogen-solid interaction requires accurate
and reliable tools. Simultaneous analyses of different properties give invaluable information for the materialscientist, especially when the repetition of experiments is challenging (small quantity of synthesisedmaterial, lack of reversibility, slow kinetics).

Introduction
The gas sorption Sievert’s technique has
proven to have many advantages over theother techniques for the evaluation of thead/ab-sorbed amount of hydrogen by thematerials in a wide range of temperature andpressure. In addition, there is a total freedom
in the size and shape of the sample holder inthe volumetric technique, enabling thecouplingoftechniquesandin-situmeasurements of various chemical andphysical parameters. X-rays and neutrons
diffractomers,
mass
spectrometers,

calorimeters have already been successfully
tested and allow to have simultaneous PCT
isotherms and kinetic measurement withstructural,gascompositionorthermodynamic data.

Results
The presentation will give an overview of thestate-of-the art possibility of combined
analysis together with the Sievert’s techniqueand an insight on the on-going projects andperspectives.

Corresponding author: Emmanuel Wirth, email: emmanuel.wirth@setaram.com, Tel. (+33) (0) 472103588

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Vibrational Spectroscopy as a Probe for structure andDynamics of Inorganic Compounds
Hans Hagemann
Dépt. de Chimie Physique, Université de Genève, 30, quai E. Ansermet CH1211 Geneva 4
Switzerland, email: hans-rudolf.hagemann@unige.chVibrational spectroscopy is a valuable tool to probe structural and dynamic properties.
In the case of borohydrides, the local symmetry of the BH4- is reflected by the site group splittingof the two degenerate bending modes of the free ion. The stretching mode region iscomplicated by the presence of important Fermi resonances.
The structure of the new compound LiSc( BH4)4 has been analyzed by a combination ofvibrational spectroscopy, theoretical analysis and X-ray crystallography. The local structure of
the Sc( BH4)4 complex, suggested by the vibrational spectra, was confirmed by DFT
calculations. The calculated atomic positions were successfully used as input for the powder Xray structure analysis.
Temperature dependent Raman spectra of LiBH4 reveal different types of dynamic properties.
The analysis of the linewidth of the bending modes vs temperature allows to estimate
reorientation barriers of the borohydride group, which are quantitatively in good agreement withother experimental determinations.
The temperature evolution of the splitting of the ν2 mode, in conjunction with the anormal
variation of the lattice parameters can be associated with a pretransition behavior towards ahypothetical higher symmetry structure which is preceeded experimentally by the first ordertransition at 381K.
The temperature dependence of the low frequency Raman spectra reveal for some bands animportant anharmonic behavior which can only partially be described by a volume
anharmonicity (associated with the thermal expansion). Other contributions will be discussed.
Finally, first single crystal inelastic X-ray scattering data on NaBH4 will be presented.

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Inelastic Neutron Scattering Spectroscopy of molecular
Hydrogen in porous Materials
A.J. Ramirez-Cuesta
ISIS Facility, Rutherford Appleton Laboratory, STFC, Chilton, Didcot, OX11 0QX, United
Kingdom
The interaction of molecular hydrogen with surfaces and porous materials can be studied with Inelastic
Neutron Scattering Spectroscopy (INS). In particular the rotational line of hydrogen is very sensitive to theinteraction of the molecule with the adsorption site. A series of results arising from the interaction ofhydrogen with different system is presented. From the weak interaction of molecular hydrogen with carbon
to the stronger interaction with metal organic frameworks.

Introduction
Inelastic neutron scattering spectroscopy(INS) is an ideal technique to study hydrogencontaining materials.[1]. Another great
advantage of INS is that allows a more directcomparison between experimental results
and theoretical calculations than is the casefor optical spectroscopies (Raman and Infrared). All experiments have been made in
TOSCA, that is the world’s higher resolution
broadband INS spectrometer. It measures arange of 3-1000 meV (24-8000 cm-1).

effect, due to the curvature of the surface ismore pronounced but still small. For metaloxides, MOF, zeolites etc, the interaction ofmolecular hydrogen is large, so are therotational line shifts [5]. For MOFs, a veryexquisite assignment of the adsorption sites
can be done.

TheoryThe rotational levels for the hydrogenmolecule, in the case of solid hydrogen(negligible interaction between molecules) is
given by:
EJM=J(J+1) Brot
Where J and M are the rotational quantum
numbers. In the case hydrogen, the rotational
constant B is 7.35 meV. With INS, due to thenature of the neutron with matter, we canmeasureanextremely
sharp
line
corresponding to the rotational transition
J(1←0) (para to ortho-hydrogen), that has anenergy of 2B (14.5 meV) [1,2].
When the hydrogen molecule interacts with asurface, the rotational line can experience ashift and splitting. In the case of graphite,
there is a very small widening of therotational line. For carbon nanotubes, theFig 1. The INS spectra of hydrogen in HKUST asfunction of loading, 4 different sites are apparent;
the population is monitored by the area of eachpeak.

References[1] PCH Mitchell, SF Parker, AJ Ramirez-Cuesta
and J Tomkinson “Vibrational Spectroscopy with
Neutrons” World Scientific, London, (2005).
[2] Ramirez-Cuesta, AJ;et al; Journal Of Materials
Chemistry, 17: 2533 (2007)[3] Ulivi, L; Celli, M; Giannasi, A; Ramirez-Cuesta,
AJ; Bull, DJ; Zoppi, M, PRB, 76: 161401 (2007)[4] Ramirez-Cuesta, A. J.; Mitchell, P. C. H.
Catalysis Today 2007, 120 (3-4), 368-373.
[5] F.M. Mulder, T.J. Dingemans, H.G. Schimmel,
A.J. Ramirez-Cuesta, G.J. Kearley; Chemical
Physics, in press.

Corresponding author: AJ Ramirez-Cuesta, email: Timmy.Ramirez-Cuesta@stfc.rl.ac.uk, +44 1235446510

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Hydrogen Dynamics in LiBH4 studied by Quasielastic
neutron Scattering
Arndt Remhof#, Florian Buchter#, Flavio Pendolino#, Pascal Martelli#, Jan PeterEmbs*, Andreas Züttel##

Empa Materials Science and Technology, Department of Energy, Environment & Mobility,
Section Hydrogen & Energy, CH-8600 Dübendorf, Switzerland*Laboratory for Neutron Scattering, ETH Zürich & Paul Scherrer Institut, CH-5232 Villigen,
Switzerland

Incoherent inelastic and quasielastic neutron spectroscopy (INS and QENS) have been
employed to analyze the hydrogen dynamics within Li11BH4. The phase transition isaccompanied by a sudden increase of the quasielastic line broadening, which can be attributed
to a lowering of the apparent activation energy for rotational reorientation.

Introduction
Due to their high volumetric and gravimetrichydrogen density, tetrahydroborates such as
LiBH4, NaBH4 and Ca(BH4)2 are currently
discussed as possible future hydrogenstorage materials [1]. However, theirtechnical utilization is hindered by their
inappropriate thermodynamic stability and by
slow sorption kinetics. Incoherent inelastic
and quasielastic neutron spectroscopy (INSand QENS) have been employed to analyzethehydrogendynamics
withinthiscompounds. The phonon densities of states(PDOS), obtained from INS give direct
evidence for disorder in the high-temperaturephase of LiBH4, which is attributed to theorientational disorder of the BH4 units [2].

Experimental
The experiments were performed at the timeof-flight spectrometer for cold neutrons
FOCUS at the Swiss spallation source(SINQ) at the Paul Scherrer Institute in
Villigen, Switzerland. Due to the large
incoherent cross section of hydrogen, thePDOS mainly represents the partial PDOS ofhydrogen. The INS measurements werecarried out in neutron energy gain mode;

therefore at the measured temperatures,
energies up to 40 meV were reasonably
accessible. Incident neutron wavelength of4Å and 6Å were selected to adjust theenergy resolution of about 60μeV and200μeV, respectively to the selected.

Results
QENS is sensitive to the rotational dynamics
of the BH4 units. The phase transition isaccompanied by a sudden increase of thequasielastic line broadening, which can be
attributed to a lowering of the apparent
activation energy for rotational reorientation.
The line-shape can be fitted to jumprotational motion.
From the Arrhenius behaviour of thequasielastic
broadening
theapparent
activation energies could be determined tobe 0.06eV and 0.2eV for the low and the hightemperature phase of LiBH4, respectively.

References[1] A. Züttel et al., Scripta Mater. 56 (2007) 823828.
[2] F. Buchter, et al., Phys. Rev. B 78 (2008)
094302.

Financial support by the Swiss National Foundation (project numbers 200021-119972, 200021-111683 and 200020115875) and by the European Commission DG Research (Contract No. MRTN-CT-2006-032474/HYDROGEN) is
gratefully acknowledged

Corresponding author: Arndt Remhof, email: arndt.remhof@empa.ch, Tel. (+41) (44) 823 4369

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Posters Monday

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Synthesis of Ca(BH4)2 by reactive ball milling.
Carine Rongeat, L. Schultz and O. GutfleischIFW Dresden, Institute for Metallic Materials, Helmholtzstrasse 20, D-01069 Dresden, Germany
Different routes were applied to the synthesis of Ca(BH4)2 using reactive ball milling under highH2 pressure. Limited reaction yield were obtained when starting from a mixture of CaH2 andCaB6 with different additive. However, considering that the process occurs at room temperature
this result is already encouraging. Higher yields can be obtained by reacting CaH2 and MgB2 toform the reactive hydride composite Ca(BH4)2 + MgH2

Experimental
The starting materials for pure Ca(BH4)2 were
CaH2 + CaB6 with different additives. The
reactive hydride composite Ca(BH4)2 + MgH2
was obtained from CaH2 and MgB2. The
mixtures were ball milled under high H2
pressures (100-140 bar). The vial usedallows in-situ monitoring of the pressure andtemperature during synthesis.

Results
A reaction yield of 22% was obtained bymilling CaH2 and CaB6 under 140 bar H2 atroom temperature. This yield is encouraging
since the synthesis of Ca(BH4)2 so far has
been only achieved using high temperaturesand high hydrogen pressures. Although no
hydride phase could be identified by XRD in
the as-milled powder, the decomposition of
the sample releases H2 in two steps uponheating to 500°C. Another route to obtainsuitable compounds is to tune the

70
65
60

155

55
50
150

45
40
35

145

30

Temperature /°C, squares

Among potential candidates for hydrogenstorage Ca(BH4)2 is very interesting because
it can release 9.6wt% of H2 and the predictedenthalpy of its decomposition [1] into CaH2
and CaB6 is 32 kJ mol(H2)-1 which meansthat only moderate operation temperatures
would be necessary. Nevertheless, thesynthesis of Ca(BH4)2 from CaH2 and CaB6 isvery difficult because of the high stability of
CaB6. In this study, this synthesis route was
performed using high pressure reactive ball
milling.

thermodynamic properties by changing thedecomposition path. For the system
Ca(BH4)2 + MgH2 (8.3wt% H2), the formationof MgB2 during decomposition facilitates thereversible absorption of hydrogen [2].
However starting from a mixture of CaH2 +MgB2, the formation of a ternary phase
Ca19Mg8H54 was found to prevent theformation of Ca(BH4)2 and limit the cycling
properties. Better results were obtained bymixing CaH2 and MgB2 with a catalyst by
milling under H2 and hydrogenating the
mixture in a second step under 100 bar H2 at
350°C. The hydrogenated sample releasehydrogen in two steps which have been
identified by a combination of DSC and XRD
analysis.

Pressure /bar, solid line

Introduction

25
140

0

5

10

15

20

25

20

Milling Time /hFig. 1. Variation of the pressure and temperatureduring milling of a mixture 2 CaH2 + CaB6 + add.

References[1] Miwa et al., Phys. Rev. B. 109 (2005) 155122.
[2] Barkhordarian et al., J. Phys. Chem C. 112(2008) 2743.

Corresponding author: Carine Rongeat, email: c.rongeat@ifw-dresden.de, Tel. (+49) (351) 4659 669

673rd Hydrogen & Energy Symposium

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Hydrogen Sorption Properties of modified Calcium
borohydride
Christian Bonatto Minella, Gagik Barkhordarian, Ulrike Bösenberg, Martin
Dornheim, Torben R. Jensen*, Rüdiger Bormann,
GKSS Research Centre Geesthacht GmbH, Institute for Materials Research, D-21502
Geesthacht Germany, *Interdisciplinary Nanoscience Center (iNANO) and Department ofChemistry, University of Aarhus
Ca(BH4)2 is considered as one of the most promising light weight complex hydrides forhydrogen storage1. Recently, some transition metal fluorides and chlorides have shown topositively affect the formation of Ca(BH4)2 2,3. In addition, the decomposition temperature ofCa(BH4)2 has been reported to decrease if such additives are used. In the present work theeffect of TiF4 on the above mentioned reactions is investigated. The evolution of phases duringhydrogen sorption is observed by time resolved synchrotron powder X-ray diffraction (SR-PXD).
Reactions kinetic are evaluated by titration measurements.

Introduction
Recently, complex borohydrides havereceived wide attention because of their lightweight and high hydrogen content. Amongthem Ca(BH4)2 seems to be the mostpromising, due to its thermodynamic
properties and rather low decomposition
temperature.

Experimental
The sorption mechanism of ball-milled
Ca(BH4)2 with TiF4 additive is studied by insitu time resolved X-ray powder diffraction
and the kinetics has been evaluated bytitration experiments. Two different tests, invacuum and with hydrogen pressure, havebeen carried out to understand if theatmosphere plays a role in the reversible
formation of Ca(BH4)2.
Ca(BH4)2 was synthesized by heating theCa(BH4)2.2THF complex in vacuum at 200°C
for 1h and 30 minutes. By that a mixture of
the low temperature and high temperaturephases was obtained. 0.05 mol of TiF4 wereadded to the borohydride and then milled in astainless steel vial with a ball-powder ratio of
14:1. Thermovolumetric measurements were

performed in vacuum and under H2 pressurein the temperature range of RT to 450°C. In
situ time resolved X-ray Powder Diffraction(PXD) desorption experiments were done
under vacuum as well as at 3 bar H2pressure in the same temperature range. The
respective in situ hydrogenation PXD
measurements were performed at 150 and
185 bar H2 pressure within the temperature
range of 30 °C to 400°C.

Results
Ca(BH4)2 milled with 0.05 mol of TiF4 is foundto be partially reversible at 450°C and 50 bar.
However, X-ray Powder Diffraction after
absorption tests did not show any
Ca(BH4)2 crystalline peaks, which suggests
the presence of an amorphous phase ofCa(BH4)2.

References[1] Barkhordarian et al., J. Phys. Chem. C 112(2008) 2743-2749.
[2] Kim et al., Scripta Mat. 58 (2008) 481-483.
[3] Kim et al., J. Power S. 181 (2008) 140-143.

Corresponding author: Christian Bonatto Minella, email: Christian.Bonatto@gkss.de, Tel. +49-(0)4152-87-2601

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Hydrogenation processes at low pressures in the NaMg-B system prepared by reactive Ball Milling
D. Pottmaier10, S. Garroni2, M.D. Baró2, M. Baricco1
1
2

Dipartimento di Chimica IFM and NIS, Università di Torino, 10125, Torino, Italy
Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain

Reactive Hydride Composites (RHC) approach consists in combining two light hydride systems
in order to lower desorption enthalpy. The RHC studied in this work is in the Na-Mg-B system,
synthesised by Reactive Ball Milling (RBM). RBM of NaH + MgB2 compounds was carried out ina Fritsch Planetary Mill under a 50 bar hydrogen pressure, 20:1 ball to sample ratio, at 300 rpm,
for 20 hours. In order to elucidate the sorption properties of this system at different
temperatures (from 250ºC up to 450ºC) and at low pressures (up to 15 bar) measurements
were performed using an Intelligent Gravimetric Analyzer (IGA). The common features of theisotherms at low pressures measured for the RHC system bear a resemblance to each other.
Moreover, analysis of X-ray diffraction pattern of this RHC after IGA measurements at low
pressures shows peaks corresponding to formation of hydride phases (NaBH4, MgH2, NaMgH3).

Introduction
Better understanding of the solid-state
reaction related to the hydrogenation of the
Na-Mg-B system is required. In this work,hydrogenation of the Reactive HydrideComposite (RHC) [1] 2NaH + MgB2 preparedby Reactive Ball Milling (RBM) is investigatedusing an Intelligent Gravimetric Analyzer(IGA). Analysis of the absorption reaction at
low pressures was performed at different
isotherm temperatures. The RHC is
compared to the pure mixture of 2NaH plus
MgB2
duringhydrogenabsorption
experiments.

Experimental
The 2NaH + MgB2 sample, identified as deRHC herein, was prepared by RBM in a
molar proportion 2:1 according to thefollowing milling conditions: Fritsch planetary
mill P5, 300 rpm (rotation speed), 20 hours(duration), ball to sample ratio of 20:1,
hydrogen pressure of 50 bar. Analysis ofhydrogenation process of the de-RHC wasmonitored by weight variation within an IGA(Hiden). Hydrogenation and dehydrogenation
processes were investigated in isotherm
mode. Preliminary sample outgas at isotherm

temperature was conducted until weight loss
was undetectable. Thereafter, isotherms at
250ºC up to 450ºC in function of the de-RHC
weight were measured with gradually
introduction of hydrogen into the sample
chamber up to 15 bar in intervals of 1 bar.
The structure of the sample before and afterhydrogenation was analysed by X-ray
diffraction (XRD).

Results
Examination of XRD patterns of the de-RHC
after RBM reveals no reaction with hydrogen
during milling, even though it shows abroadening of the peaks. During isotherm
measurements, even at low pressures, thede-RHC absorbed hydrogen. Possible
uncertainties in the thermogravimetricmeasurements
may
come
from
contamination of the sample during loading.
XRD patterns obtained for the de-RHC
sample at the end of the IGA measurement
showed hydrogenated phases such as
NaBH4, MgH2 and NaMgH3.

References[1] Barkhordarian, G. et al., J. Alloys Compd. 440(2007) L18-L21.

Corresponding author: D. Pottmaier, email: daphiny.pottmaier@unito.it, tel. (+39) (011) 570 7573

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True Activation energy of decomposition of Lithium
Borohydride LiBH4
Flavio Pendolino, Andreas Borgschulte, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The decomposition of lithium borohydride (LiBH4) is studied at non-isothermal condition undervarious hydrogen pressures. A new model is used to calculate the “true” activation energy (Ea)of the decomposition of LiBH4. The model takes into account the thermodynamics of the solidgas reaction. The procedure may be applied to similar reactions, such as the decomposition ofother borohydrides.

Introduction
The evaluation of the activation energy (Ea)of solid state reactions is usually performedby plotting the rate maxima measured bythermo desorption spectroscopy in a socalled Kissinger plot. However, thisprocedure fails, when finite pressures areapplied. We measured the decomposition oflithium borohydride (LiBH4) at varioushydrogen pressures and we proposed amodel for calculating the “true” activationenergy and taking into account the effect ofhydrogen pressurebalance equipped with a high pressure
system between 25°C and 500°C with aconstant heating rate (β) at various appliedhydrogen pressures between vacuum and100 bar. During the experiment, the sample
is covered with amorphous boron.

Results
From the rate maxima TD as a function of theheating rate the activation energy Ea can becalculated [2]. Deviations from the expected
linear behavior in a Kissinger plot can be
explainedtakingintoaccount
thethermodynamic properties, [4] that is theenthalpy and entropy of decomposition ΔHR
and ΔSR as
ln

TD

β

2

=

⎡
⎢
E a
− ln ⎢
⎢
RT D
⎢ exp
⎢⎣

p
⎛
Δ H R
Δ S R
+
⎜⎜ − RT
R
D
⎝

⎤
⎥
⎥
⎞ ⎥
⎟⎟ ⎥
⎠ ⎥⎦

The model gives Ea= 57±2 kJ/mol, ΔHR = 76
± 2 kJ/mol and ΔSR = 131 ± 2 J/mol K, inagreement with recently published pcT databy Mauron et al. [3]Decomposition rate of LiBH4/B at varioushydrogen pressures at a heating rate of
β = 6°C/min.

Experimental
The thermograms are recorded with acustomized Rubotherm magnetic suspension

References[1] H. E. Kissinger, Anal. Chem. 29 (1957) 1702.
[2] P. Mauron et al., J. Phys. Chem. B, 112 (2008)906.
[3] M. Reading, et al., J. Thermal Analysis, 37(1991) 2165- 218.

Corresponding author: Flavio Pendolino, email: flavio.pendolino@empa.ch, Tel. +41 44 823 4776

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Kinetic Features in the H2 Sorption by NaBH4 + MgH2
Composites under mechanical Activation Conditions
G. Mulas1*, S. Enzo1, S. Medici1, F. Delogu2, S. Garroni3, M.D. Barò3,
S. Surinach3, C. Milanese4, A. Marini4
1

Dipartimento di Chimica, Università di Sassari, Via Vienna 2, I-07100 Sassari, Italy;
Dipartimento di Ingegneria Chimica e Materiali, Università di Cagliari, Piazza d’Armi, I-09123 Cagliari,
Italy;
3
Dept. Física, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain;
4
C.S.G.I., Dipartimento di Chimica Fisica "M. Rolla", Università di Pavia, Viale Taramelli 16, 27100 Pavia,
Italy.
2

Materials for hydrogen storage have been receiving rising interest in view of their technologicalrelevance, related to vehicular applications. Particular attention has been recently devoted onreactive hydrides thermodynamic destabilization, able to decrease the hydrogen desorption
temperature with respect to the component phases also keeping a high hydrogen storage
capacity [1,2]. The extent of the destabilization, as well as the cycling sorption features of thecomposites, appear to depend on several factors, with the powders particles size andmorphology and the structural and nanostructural properties of the constituent hydrides playing
a key role. All these parameters are in turn strongly affected by the followed preparation route.
In this work, we evaluate the influence of different mechanical activation conditions on thestorage properties (desorption pathway and kinetics) of NaBH4 – MgH2 composites.

Introduction
Following a previously developed experimental
methodology to evaluate collision frequency,
energy delivered at the impact and intensity ofmechanical treatment, in this work we focus on
the properties of NaBH4 + MgH2 composites withdifferent stoichiometry, prepared under different
atmosphere, (Ar, H2), and impact intensity. We
investigate the H2 storage capacity and sorption
kinetics, as well as the desorption temperatures ofthedifferent
dehydrogenation
steps,
bycalorimetric and volumetric analyses. The sorption
properties are related to the morphological andcompositional characteristics of the as milled
mixtures, studied by scanning electron microscopy
and X-ray powder diffraction analysis.

Experimental
NaBH4 and MgH2 powders were milled in different
ratio (1:1, 1:2, 2:1) and under different
atmosphere (Ar, H2) by means of a Spex
Mixer/Mill mod. 8000. Powder amounts of 8 g
were sealed, together with a 12 g ball, inside astainless steel cylindrical reactor and processed at
different RPM. The morphological characteristicsof the as milled powders were analyzed by the
Scanning Electron Microscope (SEM) Jeol JSM6300. The calorimetric profiles were acquired by

Sensys DSC (Setaram) by heating about 10 mg ofsample from 250°C to 550 °C at β = 3°C/min andH2 pressure = 0.4 bar. The desorption profiles
were acquired by PCTPro-2000 (Setaram & HyEnergy) by heating about 500 mg of sample from
250°C to 450 °C at β = 2°C/min and starting H2pressure = 0.1 bar.

Results
SEM and XRPD analysis demonstrated thatdifferent particles sizes and shapes are obtainedin function of the stoichiometry and the millingparameters. The calorimetric and the thermal
desorption programmed analysis allow to
distinguish different dehydrogenation steps. The
first one, i.e. the dissociation of MgH2, starts at
about 340 °C and is almost completed at 390°C,
when the formed free Mg starts to react with
NaBH4, causing its decomposition. Work is inprogress to determine the effect of the mixtures
stoichiometry on the onset temperatures of theprocesses.

References[1] John J. Vajo et al., Scripta Mater, (2007) 56,
829-834.
[2] G. Barkhordarian et. al., J. Alloys. Comp.,(2007), 440, L18-L21.

Corresponding author: Gabriele Mulas, email: mulas@uniss.it, phone: +39 079 229524

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Evidence of formation of LiBH4 by high energy ball
milling of LiH and B
Filippo Agresti and Ashish Khandelwal
Università di Padova, Dipartimento di Ingegneria Meccanica – Settore materiali and CNISM, via
Marzolo 9, I-35131 Padova, Italy
The formation of LiBH4 by high energy ball milling a mixture of LiH and crystalline B in hydrogen
atmosphere is demonstrated. Five samples have been prepared at hydrogen pressures up to 10
atm and milling times up to 138 h. It is observed by thermal programmed desorption that theamount of released gas increases by increasing milling time, hydrogen pressure into the vial
and by using WC balls instead of stainless steel balls. The white crystalline powder obtained
from the milled material by solvent separation has been identified by X-ray diffraction as pure
LiBH4.

Introduction
In this work we demonstrate for the first time,
as far as we know, the possibility of formationof LiBH4 at room temperature by high energy
reactive milling of the decomposition
products of reaction:
LiBH4 → LiH +B + 3/2 H2Experimental
Samples of 1.0 g were obtained by mixing
LiH powder and small B pieces in the
stoichiometric ratio 1:1. The samples were
processed in hydrogen atmosphere by highenergy ball milling with a SPEX 8000M mill ina stainless steel vial using stainless steel or
WC balls (ball to mixture ratio of 30:1). Five
different samples were prepared: samples A,
B, C, D by ball milling with stainless steel
balls in 3 atm H2 for 12 h, 3 atm H2 for 30 h,
4.5 atm H2 for 120 h and 10 atm H2 for 138 h,
respectively; sample E was milled using WC
balls in 10 atm H2 for 138 h. One g of milled
sample E was put in 70 ml of methyl tertbutyl ether and stirred for 12 h under argon
atmosphere. The suspension was thenfiltered and the obtained solution was

evaporated under dynamic rotary pumpvacuum. After the complete evaporation ofsolvent, the white crystalline light powder
obtained was identified by X-ray diffraction as
pure LiBH4.

Results
TPD measurements of produced samples
showed that sample A starts desorbing ataround 300 °C with the maximum rate ataround 460 °C, while samples B, C, D, E
start desorbing at temperatures slightly
higher than RT (about 80 °C). The maximum
desorption rate is around 255 °C, 347°C,
335°C and 364 °C for sample B, C, D andE, respectively. The desorbed H2 increases
with increasing time of milling and hydrogenpressure inside the vial. Moreover, it is higher
in case of WC balls used instead of stainlesssteel balls. In particular, sample E desorbs
about 3 wt% H2. It has been demonstrated bysolvent separation, X-ray diffraction and DSC
measurements that hydrogen comes from
amorphous LiBH4 and that chemicalsurrounding and amorphous-like state
improve its decomposition reaction.

Corresponding author: Filippo Agresti, email: filippo.agresti@unipd.it , Tel. (+39) 049 827 5828

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Catalytic Role of Nanostructured Carbon on NaAlH4
Hydrogen Sorption
Ashley C. Stowe1,2, Polly A. Berseth2, Andrew G. Harter2, Ragaiy Zidan2,
Andreas Blomqvist3, C. Moysés Araújo3, Ralph H. Scheicher3, Rajeev Ahuja3,4,
and Puru Jena5
1

B&W Y-12 National Security Complex, Oak Ridge, TN 37831

2

Savannah River National Lab, Aiken, SC 29803;

3

Uppsala University, Uppsala, Sweden;

4

Royal Institute of Technology, Stockholm, Sweden;

5

Virginia Commonwealth University, Richmond, VA 23284

A systematic study of the catalytic role of carbon nanostructures on hydrogen
release and absorption of NaAlH4 has been conducted with a Seivert’s typeapparatus. These experimental results were compared with synergistic firstprinciples ab initio molecular dynamics simulations in order to elucidate theorigin of catalytic behavior within the NaAlH4 molecule. NaAlH4 interaction with
an electronegative substrate such as carbon nanotubes inhibits charge transferfrom the Na+ cation to the alanate unit thereby weakening the Al-H bond. The
result is catalytic dehydrogenation at suppressed temperatures as well as
reversible absorption of 1.5 – 4.3 wt % H2 to reform the NaAlH4 material.
Carbon fullerence (C60) showed the best catalytic behavior for rehydrogenation.

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Liquid Phase Synthesis of Magnesium Amide andAmide based Hydrogen Storage Materials
Mitsuru Matsumotoa, Masakazu Aokia, Tatsuo Noritakea, Nobuko Ohbaa,
Kazutoshi Miwaa, Shin-ichi Towataa, Satsuki Kitajimab, Masahiro Satob, Hai-wen
Lic, Shin-ichi OrimocaToyota Central R&D Labs., Inc. Nagakute, Aichi 480-1192 Japan
KRI, Inc. Kyoto Research park, 134, Chudoji-Minami, Shimogyo-ku, Kyoto 600-8813 Japanc
Institute for Materials Research, Tohoku University, Katahara 2-1-1, Sendai 980-8577 Japanb

A new synthetic route of magnesium amide, Mg(NH2)2, is described. Solution of organo-magnesium
compounds were prepared from Grignard reagents, then reacted with ammonia gas at ambient condition
to obtain Mg(NH2)2. Newly developed Mg(NH2)2 containing hydrogen storage materials will be discussed.

Introduction
A mixture of magnesium amide, Mg(NH2)2,
and lithium hydride, LiH, desorbs and reabsorbs hydrogen as much as 9wt%.
Mg(NH2)2 has been synthesized byhydrogenation of Mg3N2, or prepared by
MgH2 ball-milling under high pressure NH3
atmosphere. It has been sought that facile
Mg(NH2)2 preparation without handling highpressure/temperature H2 or NH3 gases.

with LiH showed a H2 desorption peak at 190
oC. These result suggests that the s-Bu2Mg
reacts with NH3 under mild condition (<100oC, 1atm NH3) and forms Mg(NH2)2.

Experimental
Organo-magnesium compounds, R2Mg, wereprepared by disproprtionation of Grignard
reagents. Subsequently the R2Mg solution
was scrubbed with NH3 gas for 2 hr to form
white precipitation. Expected reaction is:
R2Mg + 2NH3 Î Mg(NH2)2 + 2RH (1).
The reaction took place at room temperatureand completed by heating to 90 oC.

Results
The reaction products of eq (1) depend on
the starting R2Mg and they are categorized
as follows; (i) organo-Mg amide, (ii)Mg(NH2)2, (iii) Mg ammine compounds. The
s-Bu2Mg derived compound decomposed
around 320oC to desorb NH3, and the mixture

Fig 1. TPD-MS profile of s-Bu2Mg derived
compound (top) and the mixture with LiH (bottom).

Magnesium amide has been known to form areversible hydrogen storage material after
mixing with LiH. We are now developing a
new class of hydrogen storage materials, that
contain Mg(NH2)2 and metal borohydrides,
such as Mg(BH4)2.

Acknowledgements
This study was partially supported by the
New Energy and Industrial Technology
Development Organization (NEDO).

Corresponding author: Mitsuru Matsumoto, email: e1345@mosk.tytlabs.co.jp, tel (+81) (561) 71 7263

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Identification of structural Phases of [CaBH4]2 byNuclear Mmagnetic Resonance Spectroscopy
P. Martelli*1),2), A. Remhof 1), A. Züttel 1),2), M. Ernst 3)
1) Empa Materials Sciences and Technology, Div. "Hydrogen and Energy" Überlandstrasse 129,
CH-8600 Dübendorf
2) University of Fribourg, Physics Department, Perolles, CH-1700 Fribourg3) ETH Zürich, Physical Chemistry, CH-8093 Zürich
A future hydrogen economy requires dense, safe, efficient and reversible hydrogen storage materials withhigh sorption kinetics at convenient working temperatures [1]. Due to their outstanding volumetric andgravimetric hydrogen density, tetrahydroborides are currently discussed as possible hydrogen storage
3 [2]material. Ca[BH4]2 has a gravimetric density of 11.5% and a volumetric density of 130kg/m . However,its technical application is hindered by its high working temperature and by its slow sorption kinetics. In
order to understand the mechanisms of hydrogen loading and unloading, the structure and the hydrogendynamics of Ca[BH4]2 have to be known. Nuclear magnetic resonance (NMR) is an element specifictechnique, appropriate to observe both, dynamic processes as well as the local chemical environment.

Experimental

Results
Three different structural phases of Ca[BH4]2
can be observed by NMR. Each phaseshows a distinct chemical shift. X-ray powder
diffraction allows identifying the phases
observed with NMR to crystallographic
phases [3].

6

2x10

Intensity

Ca[BH4]2 samples from different commercial
suppliers (Sigma Aldrich) and research
institutes (GKSS, Germany, FZK, Germany,
KIST South Korea), prepared in different
ways were investigated at the NMR
laboratories at the ETH in Zürich. A Bruker
Cryomagnet (BZH 400/89) with an external
field of 3.9 T was used at the resonant linesof 11B and 1H at 128 MHz and 100 MHz,
respectively. To increase the resolution, thesample was spun at 10’000 s-1 at the "magic
angle" of 54,74°. Further improvement wasachieved by decoupling the 11B signal fromthe 1H signal. The figure shows the effect ofspinning and decoupling on the example of aphase mixed γ/α phase sample.
X-ray powder diffraction was carried with Cu
Kα radiation out using a commercial Bruker
D8 advance instrument, equipped with a 1DVåntec detector.

Ca[BH4]2

Sigma Aldrich,
98% β, 2% α, 0% γ
FZK,
1/3 β, 1/3 α, 1/3 γ
Kist,
95% α, 5% γ, β

β - phase6

1x10

α - phase0

α - β - γ - phase

-40

-30

-20

[ppm]

Effect on accuracy with MAS and decoupling

The different phases also show different
spin-lattice relaxation times in magnetization
recovery experiments.

References
[1]
[2]
[3]

Schlapbach L.; Züttel A; Borgschulte A.; Hydrogenas a future energy carrier; Wyley-VCH; Weinheim;
2008
Züttel A.; Orimo SI.; Borgschulte A.; Scripta
Materialia 2007; vol 56; 10; 823-828
Buchter, F.;Züttel, A. et Al; Orimo, S. ; J. Phys
Chem B 2008, 112 (27), pp. 8042-8048

Corresponding author: P. Martelli, email: pascal.martelli@empa.ch,

75

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Intermediates in the 2LiNH2/MgH2 Hydrogen Storage
SystemFrancesco Dolci1, Eveline Weidner2, Wiebke Lohstroh1, Maximilian Fichtner1
1

Forschungszentrum Karlsruhe- Institute for Nanotechnology; Postfach 3640, D-76021
Karlsruhe-Germany
2
European Commission-DG-JRC; Institute for Energy, PO box 2 1755ZG Petten-Netherlands
In situ neutron diffraction data about the structural evolution of the system during hydrogenation will bepresented.. The crystal structure of a new intermediate will be discussed.

Introduction
Hydrogen storage systems based on amides
have been the subject of intense
investigation since 2002 due to their highstorage capacity, good cyclability andpromising thermodynamic properties [1]. In
the last years, magnesium amide/lithium
hydride mixtures (Mg(NH2)2/LiH) have raisedmuch interest as they exhibit a highreversible hydrogen storage capacity of 5.7
wt.%, good cycling stability and favourable
thermodynamic properties[2]. However, thereaction mechanism underlying the hydrogen
absorption/desorption processes in thesesystems has not been clarified yet. [3-7].
Intermediate phases in particular are thought
to occur, but are not been clearly identified
yet [8]..

Experimental
A portable gas handling system wasdeveloped. The diffraction pattern collectedduring heating under a D2 atmosphere (70bars) a desorbed 2LiNH2/MgH2.sample
produced by ball milling.

Results
The following intermediate hydrogenation
reaction has been confirmed:
2Li2Mg(NH)2+H2⇄LiH+LiNH2+Li2Mg2(NH)3
The crystal structure of the new intermediate
Li2Mg2(NH)3 will be discussed.

References
1. P. Chen et al. Nature 420 (2002), 302.
2. W. Luo and S. Sickafoose Journal of
Alloys and Compounds 407 (2006) 274.
3. David et al. JACS 129 (2007) 1594.
4. E. Weidner et al. Chem.Phys. Lett. 444(2007) 76.
5. J. Rijssenbeek et al. Journal of Alloys andCompounds 454 (2008) 233.
6. S. Isobe et al. Journal of Physics andChemistryof
Solids(2008)
doi:10.1016/j.jpcs.2008.04.002
7. Y. Nakamura et al. Journal of Alloys andCompounds 457 (2008) 362.
8. Hu et al. J. Phys. Chem. C 111(2008) 49

Corresponding author: Francesco Dolci, email: francesco.dolci@int.fzk.de, Tel. +49-7247-82-8910

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Structure and Stability of Li2xMgy(NH)x+y
Deniz Cakir1, Gilles A. de Wijs2 and Geert Brocks1
1Computational Materials Science, Faculty of Science and Technology and MESA+ Institute for
Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
2
Electronic Structure of Materials, Institute for Molecules and Materials, Faculty of Science, Radboud
University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.

In 2002, Chen et al [1] reported reversible hydrogen storage in a mixture of LiH + LiNH2 with astorage capacity of 6.5 wt %. However, this system requires an operating temperature in excess
of 250 °C to achieve a hydrogen pressure of 1 bar. Several efforts including cation substitution
have been considered in order to improve the operating conditions, which is necessary for
onboard applications. For instance, replacing LiH with MgH2 markedly reduces the operating
temperature through the reaction MgH2 + 2LiNH2 → Li2Mg(NH)2 + 2H2. Recent experimental
evidence however indicates that the latter is not a simple one-step reaction and thatintermediate steps involve compounds Li2xMgy(NH)x+y with different Li:Mg ratios [2]. In this work
we examine the stability of these compounds by means of first-principles DFT calculations. By
calculating the formation energies of these mixed imides and their amide counterparts weestablish the likelihood of specific intermediate reaction steps.

References[1] P. Chen, Z. Xiong, J. Luo, and K. L. Tan, Nature 420, 302 (2002).
[2] J. Hu, Y. Liu, G. Wu, Z. Chiong, and P. Chen, J. Phys. Chem. C 111, 18439 (2007).

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Low temperature Raman spectroscopy of Mg(BH4)2 andMg(BD4)2
F. Gebert, B. Willenberg, and J. Schoenes
Institut für Physik der Kondensierten Materie, Technische Universität Braunschweig,
D-38106 Braunschweig, Germany

M.J. van Setten, C. Frommen, and M. Fichtner
Institute of Nanotechnology Forschungszentrum Karlsruhe, D-76021 Karlsruhe,
Germany
A low temperature micro-Raman scattering study on Mg(BH4)2 and Mg(BD4)2 is presented. We find 25
Raman-active phonon lines. A comparison with frequencies computed from first principles allows atentative assignment of all lines within the I-4m2 structure.

Introduction
With a theoretical storage capacity of 14,9
mass % hydrogen Mg(BH4)2 belongs to thecomplex metal hydrides with very large
gravimetric storage capacities. In addition, it
appears to possess close to ideal
thermodynamic properties [1,2]. Yet, its
crystallographic structure is still muchdebated. While recent X-rays studies
reported for the low temperature α-phase theP61 structure [3,4], theoretical approaches
came to various ground state structures.
Besides, the already mentioned P61 structure[1], the I-4m2 structure claimed by Ozolins etal. [5] to possess an even lower ground stateenergy, deserves special attention.

Results
We report a micro-Raman scattering study
on fine powders of Mg(BH4)2 and Mg(BD4)2
for temperatures ranging from approximately
5 K to room temperature. At the lowest
temperature, we observe 25 lines in bothcompounds. The factor group analysis for the
I-4m2 structure leads to 86 Raman activemodes. The energies of these phonon modes
have been derived using first principle

calculations based on density functional
theory.
Plots
of
the
experimentally
determined energies versus the energies of
the theoretical Raman-active phonon modes
give for the external, bending, and stretchingmodes straight lines with slopes between
0.98 and 1.03 which is better than expected.
Nevertheless, one can not definitively
conclude that the structure is I-4m2 since a
substantial number of possible lines have notbeen observed. This is even more so for the
P61 structure. Further progress will requiremeasurements on single crystals and/or
intensity computations.

References[1] M.J. van Setten, G.A. de Wijs, M. Fichtner, and
G. Brocks, Chem. Mater. 20, 4952 (2008)[2] T. Matsunaga, F. Buchter, P. Mauron, M.
Bielman, Y. Nakamori, S. Orimo, N. Ohba, K.
Miwa, S. Towata, and A. Züttel, J. Alloys Comp.
459, 583 (2008)[3] R. Cerný, Y. Filinchuk, H. Hagemann, and K.
Yvon, Angew. Chem. Int. Ed. 46, 5765 (2007)[4] J.-H. Her et al., J. Acta Cryst. B63, 561 (2007)[5] V. Ozolins, E.H. Majzoub, and C. Wolverton,
Phys. Rev. Lett. 100, 135501 (2008)

Corresponding author: Joachim Schoenes, email: j.schoenes@tu-bs.de, Tel. (+49) (531) 391 5130

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The Teller-Redlich Rule in Complex Hydrides.
A. Borgschulte1*, R. Gremaud1*, Z. Łodziana1*, Timmy Ramirez-Cuesta2, J.
Schoenes3, P. Hug1°, A. Züttel1*
1

Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, *Sec.
Hydrogen & Energy, °Sec. Solid State Chemistry, CH-8600 Dübendorf, Switzerland; 2ISIS
facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 OQX, United Kingdom;3
Institute of Condensed Matter Physics, Technical University Braunschweig, Mendelsohnstrasse
3, D-38106 Braunschweig, Germany
We will demonstrate the use of the Teller-Redlich product rule helping to assign measured vibrationalmodes in complex hydrides. The interdependencies give an intuitive understanding of the characters of thevibrating species.

ω ' = m / m' ⋅ ω(1)holds between the frequency ω’ of thephonon in the deuterated lattice (reduced
mass m’) and its frequency in the originallattice (reduced mass m). Similarly, if theextendedrigid-molecule
approximation
applies to a the complex hydride and if themode is purely librational, thenω' = I / I ' ⋅ω

(2)Here, I and I’ are the corresponding
moments-of-inertia.
The
Teller-Redlich
product-rule is a generalization of eq. (1) and

0.50

0.25

0.00

250

500

750

1000

1250

1500

NaAlH4Comparison of the frequency shifts betweenhydrogenated and deuterated samples gives
insight in the mass of the vibrating species.
When the phonon mode being probed
involves predominantly the substituted ion
type, then in first approximation the relation

0.75

NaAlH4-xDx

The Teller-Redlich rule

1.00

trans

The identification of vibrational modes insolids via Raman scattering, inelastic neutron
scattering (INS), and infrared absorption, in
conjunction with theory, is an established but
still demanding procedure. Here, themeasurement of frequency shifts induced byisotopic substitution can be helpful in sortingout the modes in complex crystals.

(2), and also holds when intermixing ofmodes occur.

intensity (1)Introduction

1750

2000

Raman shift (1/cm)

Fig. 1: Raman shift in partially deuterated NaAlH4.

We will show the applicability of the TellerRedlich-rule on Raman and INS spectra ofalanates and borohydrides. The results giveinsights into the character and coupling
between vibrational modes in complex
hydrides.

References[1] O. Redlich, Z. Phys. Chem. B 28, 371 (1935);
W. R. Angus et al., J. Chem. Soc. II, 971(1936); R. C. Casella, PRB 17, 3381 (1978).
[2] A. –M. Racu et al., J. Phys. Chem. 112, 9716
(2008)[3] A. Borgschulte et al. PCCP 10, 4045–4055(2008).

Corresponding author: Andreas Borgschulte, email: andreas.borgschulte@empa.ch, Tel. (+41) (44) 823
4639

79

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Control of Supply Subsystems of Fuel Cell Stacks
Piotr Szymak
Polish Naval Academy, Faculty of Mechanics and Electrical Engineering, Institute of ElectricalEngineering and Automatics, Śmidowicza 69, 81-103 Gdynia, Poland
In the paper state-space mathematical models of supply subsystems of a fuel cell stack and designed
regulators of supply subsystems have been presented. Moreover results of regulators’ action in the case ofstep change of load have been inserted. Numerical researches were carried out in Matlab/Simulink
environment on the base of implemented fuel cell system.

Fuel cell system consists of: a fuel cell stackor stacks, oxygen and hydrogen supply
subsystems,
thermalmanagement
subsystem and electronic power converter.
Operation and parameters of a fuel cell stack
is strictly associated with working of its
subsystems. One of the more important are
subsystems which feed reactant gases into
fuel cell stack. The most significant in supply
subsystems working is correct control of theirelements: flow rate regulators in the inlet
manifolds and pumps of gases in the
feedback manifolds (in the case the system
is closed). The control should adapt tochange of load, which force change ofreactant gases’ flow rate.

Controllers
Classical proportional-integral-derivative PID
regulators were used to control flow rates of
inlet reactant gases and control flow of gases
in feedbacks manifolds. Selection of thesecontrollers were executed on the base of
direct control quantity indexes like firstovershot, rise time and setting time,observed for flow rates of inlet gases. During
the selection process it was approached tominimization of control quantity indexes.
During simulation presented in fig.1 changesof a load were carried out: in the 5th s of
simulation increase of current density
0,5 A/cm2, in the 20th s increase of current
density 1 A/cm2 and in the 35th s decrease ofcurrent density 1 A/cm2.

Results
For the control of hydrogen’s flow rate (fig.1)
following setting times were received: 2,62 s
for increasing step of load in 20th second of
simulation and 4,49 s in 35th second of
simulation. In the result of controllers tunning,
it was received possibility of adequate
reacting by control subsystem on changes ofan electrical load.
Control of flow rate
for changes of an electrical load
flow rate H2 [Nl/min]

Introduction

100
80

Vh2in

60
Vh2in
zadane

40
20
0
0

20

40

60

80

100

time [s]Fig. 1. Control of hydrogen’s flow rate in the caseof changes of an electrical load .

References[1] Bujło
P.;„Polimerowe,superjonowe
membrany dla ogniw paliwowych typu
PEMFC”, Wrocław 2006, in polish[2] Gasser F.; “An analytical, control-oriented
state space model for a PEM fuel cell system”,
Ecole Polytechnique Federale de Lausanne,
2006[3] Pukrushpan J., Stefanopoulou A., Peng H.;“Control of Fuel Cell Power Systems”,
Advances in Industrial Control, London:
Springer,1 ed., 2004

Corresponding author: Piotr Szymak, email: p.szymak@amw.gdynia.pl, Tel. (+48) (58) 626 29 94

80

3rd Hydrogen & Energy Symposium

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Validation of a mathematical model of 5kW PEMFC
Stack supplied by pure Oxygen and Hydrogen
Józef Małecki, Piotr Szymak, Grzegorz Grzeczka
Polish Naval Academy, Faculty of Mechanics and Electrical Engineering, Institute of ElectricalEngineering and Automatics, Śmidowicza 69, 81-103 Gdynia, Poland
In the paper state-space mathematical model of PEMFC stack (proton exchange membrane fuel cell) withnominal power 5kW supplied by pure oxygen and hydrogen has been included. The model was
implemented in Matlab/Simulink environment. Moreover results of experimental verification of designed
model on the base of real fuel cell stack from Nedstack company have been presented. In summary
conclusions from working of PEMFC supplied by pure oxygen and hydrogen have been inserted.

Using of fuel cell technology to supply
objects, which do not have access to air (forexample underwater vehicles) causes needof supply a fuel cell stack by pure oxygenand hydrogen. Estimation of efficiency andothers parameters of a fuel cell stack can be
performed on the base of simulated model ofthe stack. Reliable mathematical model of afuel cell stack should be verified on the baseof measured parameters and characteristics
of a fuel cell.

Experimental verification
The state-space mathematical model of fuelcell operation in the form of differential
equations and state-space matrixes was
implemented with the aid of Simulink – one of
the Matlab toolbox. Simulated model allow toachieve characteristics of fuel cell for desired
set of input parameters for example: anelectrical load, temperature, relative humidity
and pressure of reactant gases. It allowed toreceive polarization curve presented in fig.1.
While characteristics of real fuel cell stack
were achieved during researches executed in
Nedstack
laboratories
inArnhem,Netherlands. Examined fuel cell stack has
nominal power 5 kW during air supply.

Results
On the base of presented in fig.1
comparison, it was found that parameters ofthe mathematical model were selected

correctly. Designed model can be used tofurther numerical researches.
Polarization curves U-I of model in T=65°C
and FC no. SBP200p040n001
stack voltage [V]Introduction

40
38

model
T=65°C

36
34

SBP200p
040n001

32
30
28
26
0

50

100

150

200

250

stack current [A]Fig. 1. Comparison of polarization curves ofsimulated model in temperature 65°C and real FC
stack no.SBP200p040n001.

For the stack supplied by pure oxygen,
increase of power stack was observed fromnominal value 5 kW to almost 6 kW.

References[1] Bujło
P.;„Polimerowe,superjonowe
membrany dla ogniw paliwowych typu
PEMFC”, Wrocław 2006, in polish[2] Gasser F.; “An analytical, control-oriented
state space model for a PEM fuel cell system”,
Ecole Polytechnique Federale de Lausanne,
2006[3] Pukrushpan J., Stefanopoulou A., Peng H.;“Control-oriented modeling and analysis forautomotive fuel cell systems”, internet,
http://ghost.engin.umich.edu/DS_03_1099.pdf

Corresponding author: Józef Małecki, email: j.malecki@amw.gdynia.pl, Tel. (+48) (58) 626 56 67

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Posters Tuesday82

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Conception of Power System of an underwater Vehicle
based on Fuel Cell Technology
Grzegorz Grzeczka, Piotr Szymak
Polish Naval Academy, Faculty of Mechanics and Electrical Engineering, Institute of ElectricalEngineering and Automatics, Śmidowicza 69, 81-103 Gdynia, Poland
In the paper conception of an underwater vehicle’s power system based on PEMFC (Proton Exchange
Membrane Fuel Cell) has been included. Proposed solution takes into consideration operation without air
access and underwater conditions, especially specific giving up of the heat and generated water .

Introduction
The latest news from executed researches
especially by scientists from USA inform
about unavoidable way of technologicalprogress of underwater robotics in directionof fully autonomous underwater vehicles
AUV. Basic condition of their efficient
operation is using of power source with highefficiency and independence from air. Thiskind of power source can be a fuel cell that is
an electrochemical device, which change
chemical energy into electrical energy indirect process.

Description of power system
Presented in fig.1 power system is based on
two fuel cell stack with nominal power 5 kW.
They are connected in parallel.
Stacks are supplied by closed loop oxygenand hydrogen subsystems. While thermal
system is based on heat exchanger typeliquid-liquid. Power converter DC/DC iscoupled parallel with accumulators, whatgives possibility of fast response on changeof an electrical load.
Operation of all subsystems is controlled andmonitored by modern and reliable onunderwaterconditions
programmablecontrollers Compact Rio.

Results
In comparison with used so far solutions,which are mainly based on using of energy
accumulated in the batteries, fuel cell
technology is more useful for underwater
applications especially since the technology

offer the highest gravimetric and volumetricpower density. Owning this kind of powersource can be stimulus for development of
new constructions of underwater vehicle.
Control
Subsystem

Monitoring
Subsystem

ThermalSubsystem

DC/DCElectrical
Load

Fuel
Cell
No. 1

Hydrogen Supply
Subsystem

Oxygen Supply
Subsystem

Fuel
Cell
No. 2

Fig. 1. General diagram of power system of anunderwater vehicle based on PEMFC.

References[1] Bujło
P.;„Polimerowe,superjonowe
membrany dla ogniw paliwowych typu
PEMFC”, Wrocław 2006, in polish[2] Browning D.J., Lakeman J.B.; “The Role of
Fuel Cells in the Supply of Silent Power forOperations in Littoral Waters”, Symposium on“Novel Vehicle Concepts and Emerging
Vehicle Technologies”, 2003
[3] Grzeczka G., Szymak P.; „Opracowanie
technologii
rezerwowego
zasilania
elektrycznegookrętupodwodnegozzastosowaniem
wodorowego
ogniwapaliwowego”, grant report, AMW, 2008, in
polishCorresponding author: Grzegorz Grzeczka: g.grzeczka@amw.gdynia.pl, Tel. (+48) (58) 626 29 94

83

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Tandem Cell for Hydrogen Pproduction: Examining
Hemetite-DSC Architecture Strategies
Jérémie Brillet, Kevin Sivula, Jun-Ho Yum, Morin Cornuz, and Michael Grätzel
Laboratoire de Photonique et Interfaces, Ecole Polytechnique Fédérale de Lausanne, CH-1015,
Lausanne, Switzerland
In this study we investigate the effectiveness of three different hematite-DSC tandem cell architectures forthe direct production of hydrogen by solar watersplitting. By measuring the current-voltage characteristics
and incident photon conversion efficiencies (IPCE) we were able to anticipate the current and voltage
delivered in the full system, promising a theoretical overall solar-to-hydrogen conversion efficiency of
1.39%. The study of the absorption spectrums correlated to the IPCEs allowed us to identify the need fortransparency improvement of the DSC in the UV range for a “DSC on top” configuration and the need forbetter absorption of the DSC in the NIR range for a “DSC bellow” configuration.

Introduction
Solar energy can be effectively stored byphotoelectrochemical
water-splitting
toproduce dihydrogen. We discuss here asystem for the direct solar hydrogenproduction
using
two
types
of
photoelectrochemical cells. An iron oxide (αFe2O3 or Hematite) photoanode for oxygen
evolution and a platinum counterelectrode forhydrogen evolution are connected in series
to two dye sensitized solar cells (DSC) whichassistthephotoelectrolysis.
Threearchitectures are investigated: two identical
DSCs on top of the Hematite film, two
identical DSCs below the Hematite film andtwo DSCs, with different absorption ranges,
stacked below the iron oxide film.

wavelength by the incident light spectra on
the device (solar spectrum filtered by thedevices on top).

Results
We identified the limiting factors to be thetransparency of the DSC in the range of 350
to 500 nm for a “DSC on top” configurationand the absorption of the DSC in the range of
700 to 850 nm for a “DSC below”
configuration.

Experimental
DSCs were made by the conventional
method with dyes coded as SQ1 and Black
Dye. Hematite photoanodes were made byatmospheric pressure CVD (APCVD). The
transmittance, I-V characteristics and IPCEof each device were measured underappropriate illumination depending on thearchitecture considered. The theoreticalmaximal current delivered by each device
was calculated by integrating over the full
spectrum the IPCE multiplied at eachFig. 1. Three tandem architectures.

References[1] Grätzel et al; Nature. 353 (1991) 737-739[2] Kay,A et al; J. Am. Chem. Soc. 128 (49)(2006) 15714-15721

Corresponding author: Jeremie Brillet, email: jeremie.brillet@epfl.ch Tel. (+41) (21) 693 5178

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Development of new membranes forElectrolyser Cells based on inorganic Material

alkaline

M. Gorbar 1, D. Wiedenmann 1, V.P. Zakaznova-Herzog 1, U.F. Vogt 1, B.
Grobety 2, A. Züttel 1
1

Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
2
University of Fribourg, Dept. of Geosciences, Chemin du Musée 6, Pérolles, CH-1700,
Fribourg, Switzerland
This project focuses on the development and study of new membranes for high pressure alkalineelektrolysers to substitute membranes made of asbestos, the use of which is prohibited by recent healthregulations. Suitable materials based on the chemical stability, ion conductivity and other similar toasbestos properties were sorted from literature. Considering previous work, basis materials for membranes
were defined as silicate minerals, inorganic metal oxides, titanates and organic polymers of fluorocarbon
groups. Membrane properties can be greatly improved by combining these materials to composites
sandwich-like structures and ceramics using different preparation techniques. We started testing firstprepared membranes in lab size electrolyser cell (with electrodes Ø 34 mm) at ambient conditions.

Introduction
High purity hydrogen and oxygen are
produced by high pressure alkaline
electrolysers. An important requirement in
the fabrication of hydrogen and oxygen byelectrolysis is that the anode and thecathode have to be separated by a gastight, but ion-permeable membrane.
Currently used asbestos membranes inalkaline electrolysers have to be replaceddueto
recenthealthregulations.
Membranes in alkaline electrolysers have tofulfil several requirements like highchemical and mechanical stability (e.g. 30%
KOH, 85°C, 32 bars), wettability, flexibility,
ion-conductivity. Therefore, to determine
right parameters for new materials, we first,
needtoinvestigate
theasbestos
membranes to explain its excellent
behaviour in electrolysis.

Material Selection
Based on asbestos investigations andliterature research [1-3], we define selection
criteriafornewmaterials.
Sortedinformation on the basis material andpreviously developed membranes for othertypes of electrolysers is presented.

Experiment

32 bars). Such in situ measurements require
the development of a high temperature andpressure electrochemical cell, which
includes a hydrogen/oxygen gas flow
metersandgas
purityanalyzers.
Preliminary tests, however, need to be
performed at ambient temperature andpressure. We started testing of freshasbestos membrane in lab size electrolyser
cell (with electrodes Ø 34 mm) to use it as areference point for the newly developed andprepared membranes. Fresh and used in
the electrolysis asbestos and newly
developed membranes are characterized
before and after electrolysis tests by thefollowing methods: SEM, XRD, XPS, PSD(particles size distribution) and Hgporosimetry.
Mechanical pressing and sintering is
employed as preparation techniques inorder to have different tensile strength,
porosity, and pores size distribution.

References
[1]
[2]
[3]

Vandenborre, H., et al., Int. J. Hydrog.
Energy, 10 (1985), 719.
Wendt, H., H. Hoffmann, and V. Plzak,
Int. J. Hydrog. Energy, 9 (1984), 297.
Montoneri, E., et al., J. Compos.
Mater., 21 (1987) 690.

Membrane performance needs to be tested
in the electrolysis test cell (30% KOH, 85°C,
Corresponding author: Michal Gorbar, email: michal.gorbar@empa.ch , Tel. (+41) (44) 823 4301

85

3rd Hydrogen & Energy Symposium

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Symmerty Analysis of hydrogen related structural
tramsformations
Wiesława Sikora, Agnieszka Kuna
Faculty of Physics and Applied Computer Science, AGH - University of Science andTechnology, Al. Mickiewicza 30, 30-059 Kraków, Poland
In this work we present a complex symmetry analysis of formation of structures which are known to store
large amounts of hydrogen. The criterion to select structures was based on the most popular structures of
hydrides reported in literature.

Introduction
The symmetry analysis method is able topredict all possible structural transformations
from high symmetry parent structure to thestructure with symmetry belonging to one ofits subgroups. These transformations aredescribed by small number of parameters,
independent on the multiplicity of occupied
positions and types of physical quantities,
characterizing the crystal. In situation of thehydrides this method seems to be very
helpful. We present all possible active
representations of invariable lattice fordifferent positions and for different types ofordering (modes). The subgroups of theparent group following from active IR-s andk ,νordering parameters cλl

In Tab. 1 our results for the possible site
occupation changes ΔP (for τ11) calculated
for all possible cases following from parent
group P6/mmm (191), and splitting of
P6/mmm equivalent positions to thecorresponding subgroup orbits is presented.
destinati
on groupτ11 (c’,c’)
Cmmm
(65)
i /3
c’= ce π

The analysis was made using computer
program MODY [1], with mode options: a)scalar – for a probability change of site
occupation, b) polar - for atom displacementsfrom high symmetry structure positions, andc) axial – for ordering of magnetic moments.

This analysis was already successfully
applied for Laves phase hydrides C14 andC15. In this paper symmetry analysis method
was applied for AB5 structure type - P6/mmm
space group and for the σ-phase in binary
alloys - P42/mnm space group. For observed
also Fm3m and I4/mmm space groups we
present our analysis as well.

(0, 1/2, 1/2)
6l (x, 2x, 0)(1+x,2x, 0)(-2x, -x, 0)(1-2x,-x, 0)
6m (x, 2x, 1/2)(-2x,-x, 1/2)

were calculated.

Results

Wyckoff
position in
P6/mmm3g (1/2, 0, 1/2)
(1/2,1/2, 1/2)

12n (x, 0, z)(0, x, z )12o (x, 2x, z)

ΔP

representatives of
Wyckoff positionin τ114f (1/4, 3/4, 1/2)
(3/4, 1/4, 1/2)
(1/4, 1/4, 1/2)
(3/4, 3/4, 1/2)
2c (0, 1/2, 1/2)
(1/2, 0, 1/2)
8p(x/2,3x/2+1,0)

Cg
Cg
Cg
Cg
-2Cg
-2Cg
Cl

4g (-x, 0, 0)-2Cl

8q(x/2,3x/2+1,1/2)
4h (-x, 0, 1/2)
16r(x/2,-x/2+1,z)
8n (0, x, z)
16r (x/2, 3x/2, z)
8o (-x, 0, z)

Cm
-2Cm
Cn
-2Cn
Co
-2Co

Tab. 1
References[1] W. Sikora et al : J.Appl.Cryst. 37 (2004) 1015

(http://novell.ftj.agh.edu.pl/sikora/mody.htm)

Corresponding author: W. Sikora, email: sikora@novell,ftj.agh.edu.pl Tel. (+48) (12) 6173850

863rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Alloying Effect on H octahedral vs tetrahedral Site
Occupation in Pd-Au: First Principles Calculations andNeutron Diffraction Measurements
Ali Marashdeh(1), Diana E. Nanu(1), Wim G. Haije(2), Jaap F. Vente(2), Matt G.
Tucker(3), Amarante J. Böttger(1)(1)

Dept. Materials Science & Engineering, Delft University of Technology, Mekelweg 2,2628 CD Delft, The Netherlands;(2)

Energy research Centre of the Netherlands, Westerduinweg 3, 1755 LE Petten, The
Netherlands;(3)

ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK

Existing metal membranes for H2 separation suffer from embrittlement caused by the large
volume changes that occur at H uptake and release. The design of suitable materials requires
knowledge of the stability of phases and structural changes that occur during H
absorption/desorption. Pd-Au-H(D) is chosen as a model system to investigate structuralchanges upon alloying because large changes in solubility and diffusivity of H as a function of
the Au-content are reported. The occupancy of the interstitial sites depends on the local atomic
configuration of the metal lattice. First principles calculations are performed on clusters thatcomprise both the metal lattice (Pd-Au) and the interstitial lattice. The calculations consider H(D)in the octahedral and tetrahedral sites. Different configurations for the same composition havebeen taken in consideration to investigate their relative stability. Experimentally the atom
configurations for Pd-Au-D (with 10, 20 and 25at% Au) were determined by neutron scattering.
The site occupancies obtained by full profile fits show that the presence of Au results in
occupation of also tetrahedron sites besides that of octahedral sites. The atom configurations
were determined through the analysis of the neutron scattering data by Reverse Monte Carlosimulations. The calculations and experimental results are discussed in terms of membrane
properties.

87

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3 Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Structural characterization and thermodynamic
properties of the LiBH4 – MgH2 system
A. El Kharbachi, I. Nuta, C. Chatillon, A.R. Yavari
Science et Ingénierie des Matériaux et Procédés, INP-Grenoble, BP 75, 38402 Saint-Martind’Hères, France
Abstract
The hydride system LiBH4 – MgH2 has shown interesting functionalities for hydrogen storage,1

as reported by Vajo et al. by reacting the complex hydride (LiBH4) with another compound ofbinary hydride (MgH2). Indeed, this has allowed a considerable lowering of the pressure and thetemperature during the equilibrium reaction: MgH 2 + 2 LiBH 4 ←→ MgB 2 + 2 LiH + 4 H 2 . In
other word, at given temperature the equilibrium pressure is higher than that for either LiBH4 or
MgH2 alone. This work aims at investigating the system hydride LiBH4 – MgH2, by means of Xray diffraction, scanning electron microscopy and differential scanning calorimetry.

This

preliminary study will help us to well-consider the conditions for envisaged mass spectrometric2measurements using classical Knudsen cell . The systematic identification of the gaseous
phase will be useful for the understanding of the reaction mechanisms and their kinetics during
the diffusion of the hydrogen across the different interfaces of segregation in this kind of
materials.

1

J.J. Vajo et al., J. Phys. Chem. B Letters 109 (2005) 3719

2

C. Chatillon et al., J. Phys. and Chem. solids 66 (2005) 488

88

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Improvement in the H2 Absorption Kinetics of the
Mg – Ni System by C (graphite) Addition
C. Milanese1, A. Girella1, G. Bruni1, P. Cofrancesco1, V. Berbenni1, P.
Matteazzi2, A. Marini1.
CSGI - Physical Chemistry Dept., University of Pavia, Viale Taramelli 16, I - 27100 Pavia, Italy;
2
MBN Nanomaterialia SpA, Via G. Bortolan 42, I - 31050 Vascon di Carbonera (TV), Italy.
The catalytic effect of C towards H2 absorption by Mg and Mg2Ni in ball milled samples was demonstrated.
The thermal activation of the C-doped mixtures was easier with respect to the Mg-Ni binary samples, with
the n° of cycles needed for activation decreasing by increasing the milling time. The activated doped
samples fully charged in 2min with a 100% sorption yield. Unfortunately, desorption became a little slower.

Introduction
In this work the effect of C (graphite) additionon the H2 sorption performances, thereactivity and the morphology of Mg - Ni ballmilled mixtures was deeply analyzed.

Experimental
Binary Mg 85 wt% – Ni 15 wt% mixtures(MN) and ternary Mg – Ni – C samples(MNC, with Mg 85% : Ni 15% ratio and C
amount increasing from 5 to 30 wt%) wereprepared by high energy ball milling (BM)under 5 bar Ar for two different processing
times (tBM = 2 h and 8 h).
Samples activation was performed at 350°C by subsequent charging/discharging
runs at starting H2 pressure of 50 bar/1
bar in a Sievert type apparatus. The
sorption properties of the mixtures werecharacterized (300°C≤T≤350°C) by kinetic
measurements, thermal programmed
desorption and Pressure-Composition
Isotherm (PCI) analyses. X-ray diffraction
measurements were performed on thesamples both after BM and at the end ofeach absorption/desorption step.

Results
BM did not lead to any reaction among thecomponents of the mixtures. Samples
needed to be thermally activated to reach
their effective sorption performances. In
particular, the sorption kinetics and thestorage capacity of the MN mixtures

increased noticeably with the activation
cycle number, and four runs are necessary
for full activation. For MNC samples theactivation was faster even if, surprisingly,
the number of needed cycles increased(from two to three) with tBM and the 2 h BM
mixturesshowedbetterkinetic
performances than the 8 h BM samples.
SEM and TEM analyses are currently inprogress in order to explain these results independence on the samples’ microstructure
and morphology.
In all the mixtures, the thermal treatment
induced the quantitative formation of Mg2Ni.
By charging, MgH2 and Mg2NiH4 wereobtained. On the contrary, C reacted neitherwith Mg and Ni nor with H2.
The MN samples did not reach anequilibrium content after 2h charging at
350°C, even if they showed a 90% sorption
yield. On the contrary, the MNC samples
fully charged within 2 min, with a sorption
yield close to 100%. C addition did not leadto variation in the starting dissociation T of
both MgH2 and Mg2NiH4 (280°C and 300°C
at 1bar H2), but it made the two processes alittle slower. No noticeable differences could
be seen between MN and MNC samples
concerning the PCI pressures of the two H2
active systems, but the shapes of the
Mg2NiH4 desorption curves looked different.
Studies on the dissociation mechanism of
the hydride in the two kinds of mixtures areunder development.

Corresponding author: C. Milanese, email: milanese@matsci.unipv.it, Tel. +39 0382 987670.

89

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Alkaline Salt Materials Property and Aging Study
Jonathan S. Morrell2, Katherine E. Hutchinson1, and Elena Garlea2
1

Centre College, 600 West Walnut St., Danville, KY 40422, USA

2

Y-12 National Security Complex, P.O. Box 2009, Oak Ridge, TN 37831, USA*

Alkaline salts such as lithium hydride (LiH) have been proposed as a hydrogenstorage medium for an alternative fuel economy. The thermophysical properties
and environmental characteristics of the salt must be understood in order tomanipulate the material’s performance and to prevent catastrophic failure due tothe aging process. Several analytical techniques were used to assess theseproperties and aging phenomenon. These include thermomechanical analysis(TMA) for coefficent of expansion, dynamic vapor sorption (DVS) using
thermogravimetric analysis (TGA) with a humidity controlled chamber, andFourier Transform Infrared (FTIR) and Diffuse Reflectance Infrared Fourier
Transform (DRIFT) for surveillance of the salt when exposed to various
environmental conditions. Results show a multi-step pathway for aging of thesalt and release of hydrogen depending on the temperature, kinetics, andhumidity exposure levels.

90

3rd Hydrogen & Energy Symposium

Peculiarities of Hydrogencrystalline Magnesium

Braunwald, Switzerland 2009

Interaction

with

Nano-

Konstantin Gerasimov, Stanislav Chizhik, Irina KonstanchukInstitute of Solid state Chemistry and Mechanochemistry SB RAS, Kutateladze 18, Novosibirsk
630128, Russia
Some peculiarities, revealed at hydrogen interaction with nanocrystalline magnesium such as “hysteresis”,
strong dependence of reaction rate on hydrogen pressure and incomplete transformation into hydride, areexplained on the basis of role of nucleation processes in hydriding of nanocrystalline magnesium.

Introduction
In recent years the main tendency inimproving hydriding properties of magnesium
consists in fabrication of nanocrystalline
magnesium-catalyst composites. As a rule, it
significantly accelerates hydriding anddehydriding rates. But some peculiarities inhydriding properties of nanocrystalline
magnesium have been revealed and theyshould be taken into consideration at
investigation
anddevelopmentofnanocrystalline hydrogen storage materials.
For example, some authors reported about“hysteresis” phenomenon observed in
nanocrystalline Mg-based systems [1-5],
which is not observed for magnesium
powders with an ordinary particle size (morethan 1 μm). We revealed the stronger
dependence of reaction rate on hydrogenpressure for hydriding of nanocrystalline
magnesiumthanofcoarse-grained
magnesium. The question remains why
nanocrystalline magnesium is not completelytransformed into magnesium hydride.
In this work some explanations of observed
phenomena are proposed on the basis ofrole of nucleation processes in hydriding of
nanocrystalline magnesium.

Results
Due to very low solubility of hydrogen inmagnesium, the nucleation processes playeven a more important role in hydriding of
nanocrystalline Mg than in hydriding ofcoarse-grained Mg. The number of hydrogenatoms dissolved in nano-sized particle ofmagnesium may be not enough for formationand growth of a critical hydride’s nucleus.
It may explain the «hysteresis» phenomenon.
Actually, there is no hysteresis in theinteraction of Mg with hydrogen. The
apparent «hysteresis» is caused by ahampered nucleation of MgH2 at a hydrogenpressure close to equilibrium pressure.
Initiation of nucleation by short increase ofhydrogen pressure leads to approaching theequilibrium pressure which is the same as
obtained in dehydriding process. Equilibriumpressure for nanocrystallined Mg turns out tobe lower, than for coarse-grained Mg. The
most possible reason of this is the lesser
surface energy of MgH2 than Mg.
The hampered hydride nucleation in nanosized particles may leads to decrease of totalhydrogen capacity because some particles
remain unreacted.
Increase of solubility of hydrogen inmagnesium (for example, by means ofenhancement of hydrogen pressure) should
increase the number of particles involved inreaction and consequently increase totalhydrogen capacity.

References[1] Liang et al; J. Alloys Compd. 292 (1999) 247[2] Gross, et al; J. Alloys Compd. 240 (1996) 206[3] Saita, et al; J. Alloys Compd. 446-447 (2007)
80[4] Kandavel et al; J. Alloys Compd.348 (2007)285[5] Dehouche, et al; J. Alloys Compd. 455 (2008)
432

Corresponding author: Irina Konstanchuk, email: irina@solid.nsc.ru, Tel. (+7) (913) 9203845

91

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Metallographic study on the role of catalyst particles in
the kinetics of reaction between Magnesium andHydrogen
M. Vittori Antisari, A. Montone, A. Aurora, D. Mirabile Gattia
ENEA, FIM Department, Research Centre of Casaccia, Via Anguillarese 301, 00123 Rome, Italy
The kinetics of phase transformation between Mg and MgH2 has been investigated by Scanning Electron
Microscopy in order to support the interpretation of kinetics data. An original metallographic method, basedon the low voltage observation of cross sectional powder samples able to provide information on thespatial distribution of Mg, MgH2 and catalyst particles, has been setup. Experimental work has been
carried out on composite samples synthesized by partial hydrogenation/de-hydrogenation of Mg basematerials processed by ball milling and catalyzed with Fe. Experimental results support the role of catalyst
particles is assisting several steps in the reaction sequence leading to hydrogen uptake and release.

Introduction
The role played by the catalyst in thehydrogenation/de-hydrogenation reaction of
Mg base materials is generally derived only
indirectly from the analysis of the reaction
kinetics. The support to the kinetics analysis
based on the metallographic approach is, infact, not often used in the present case,probably owing to the difficulties of setting up
reliable protocols. We have developed amethod for SEM observation of composite
samples constituted by MgH2, Mg and heavy
metal particles, synthesized by partial
reaction of catalyzed Mg with hydrogen.
Experimental results can be useful insupporting the interpretation of kinetics data.

Experimental
The method is based on low voltage SEM
observation of cross sectional powder
samples. The powder particles areembedded in a suitable matrix which allows
the metallographic preparation necessary to
expose the internal microstructure. The
contrast between Mg and MgH2 is related tothe different electronic structure of the twophases. In fact Mg is a conducting metal
while MgH2 is an insulating phase, and thisfeature can give rise to an interpretable
contrast when a SEM image is taken insuitable experimental conditions. The spatial

distribution of the two Mg based phases andof the catalyst in a partially reacted sample,
can be easily obtained from this kind ofobservation. The method has been used tosupportthekinetic
study
of
the
absorption/desorption behavior of samples
prepared by ball milling and constituted by
MgH2 with and without the addition of Fe.
Samples obtained by interrupted absorption
and desorption processes have been
observed with the purpose of identifying thenucleation site of the reaction products.

Results
Experimental results are mainly constitutedby high resolution SEM images of powdercross sections, where the nucleation sites of
the reaction products can be easily identified.
The role of the Fe particles in assisting the
Mg nucleation in the de-hydrogenation
reaction as well as the role of a fine catalyst
distribution in setting up an interconnected
microstructure are clearly evidenced.

References[1] N. Abazovic, A.L. Aurora, D. Mirabile Gattia, A.
Montone, L. Pilloni, M. Vittori Antisari
Mater. Res. Soc. Symp. Proc. Volume 1042E,
S03-22 (2008)

Corresponding author: Marco Vittori Antisari, email: vittori@casaccia.enea.it, Tel. (+39) (06) 30483119

92

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Investigation of mechanical and kinetic Stability incompacted MgH2 based Samples
Ashish Khandelwal1, Filippo Agresti1, Nicola Zanon1, Sergio Lo Russo2,
Amedeo Maddalena1, Giovanni Principi1
1

Università di Padova, Dipartimento di Ingegneria Meccanica,Settore Materiali, via Marzolo 9,35131, Padova, Italy.

2

Università di Padova, Dipartimento di Fisica and CNISM, via Marzolo 8, 35131, Padova, Italy

Mechanical and kinetic stability in MgH2 based specimens pressed in the form of pellets has been tested
with the help of a Sievert’s apparatus up to 50 cycles. Pellets of ball milled MgH2 powder catalyzed with
Nb2O5 and graphite do not behave satisfactorily. On the contrary, pellets of catalyzed MgH2 mixed withO
different concentrations of Al powder and heated at 450 C for few minutes show an improvement inmechanical as well as kinetic stability.

Introduction
Scaling up studies in the case of MgH2 based
samples show the kinetic and the storage
degradation of the specimens as comparedto the laboratory scale studies [1]. One of thepossible reasons for this degradation in
kinetic and storage behaviour is thecompaction of powders inside the storage
device during processing cycles. This
motivated us to investigate the kinetic andmechanical stability in MgH2 based pellets.

Experimental
MgH2 powder with Nb2O5 (5 wt %) andgraphite (1 wt%) was ball-milled in a SPEX
8000 shaker mill for 20 h using steel ballswith ball to powder ratio of 10:1. The milling
was done in a little overpressure of argon
atmosphere. Pellets of catalyzed MgH2
powder
withandwithout
different
concentrations of Al powder were preparedby pressing the milled powder under ahydraulic pressure of 230 MPa. Structuralcharacterization of the as-prepared powder
and the pellets after a number of hydrogen
absorption/desorption cycles was done usinga Philips PW 1820/00 X-ray diffractometerwith the CuKα radiations. Kinetic andthermodynamic tests were performed using a

Sievert’s type gas reaction controller. For thepellets with Al powder, pre-annealing was
performed in the same Sievert’s apparatus ina vacuum obtained by a rotary pump.

ResultsThe
absorption/desorption
kinetic
measurements have been performed up to
50 cycles in order to test the stability of thepellets. Pellets with 20 wt% aluminum
degrade by cycling, moreover, the hydrogencontent is low and decreases with theongoing cycles. It is found that a preheatingof the pellet at the eutectic point of Al-Mg
alloy (450°C) increases its performance. A
good mechanical stability has been observedin the case of pellets with 5 wt% aluminium
pre-heated at 450°C showing a capacity of
5.3 wt% constant up to 50 cycles and akinetics unchanged after 10 cycles. The
Al3Mg2 phase observed in the XRD patternsof the preheated pellet after 50 cycles is
propounded to stabilize its mechanicalcompactness and stability.

References[1] M. Verga et al; Int. J. Hydrogen Energy, inpress, doi:10.1016/j.ijhydene.2008.08.043.

Corresponding author: Ashish Khandelwal, email: ashish.khandelwal@unipd.it , Tel. (+39) (49) 827 5828

93

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Structural and Hydrogen sorption Properties of Mg–Ni–
Y alloys prepared by melt spinning
Siarhei Kalinichenka1, Lars Röntzsch2, Bernd Kieback1,2
1)

Institute for Materials Science, Dresden University of Technology, Dresden, Germany

2)

Fraunhofer Institute for Manufacturing Technology and Applied Materials Research, Dresden,
Germany
Two Mg-based Mg–Ni–Y alloys (Mg90Ni5Y5 and Mg80Ni10Y10) were produced by melt-spinning andcharacterized regarding their microstructure, recrystallization behaviour and hydrogen storage properties
using SEM, TEM, XRD, DSC. The hydriding properties of the as-quenched and annealed ribbons werestudied using a magnetic suspension balance, where reversible gravimetric storage densities of 4 wt.-% H
were demonstrated.

Introduction

Results

Mg-based alloys are widely know andinvestigated in view of their application asreversible hydrogen storage materials. They
are particularly interesting because of theirrather high gravimetric hydrogen capacity. In
order to enhance the hydrogen ab/desorption kinetics, Mg-alloys are often ballmilled in order to obtain a sub-µm structure
and to mix the Mg alloy with catalytic
particles like transition metal and rare earth
compounds [1].
In this study, an alternative synthesis routefor nanostructured Mg-based alloys ispursued, namely melt spinning. With this highyield rapid cooling technique a super-fine
microstructure solidifies in the form of ribbons
which are several tens of micrometer thin [2].

X-ray diffraction patterns of as-spun ribbons
reveal a superposition between a dominating
amorphous peak with overlapped sharp
peaks of Mg phases in the case of Mg90Ni5Y5
and a fully amorphous phase in the case of
Mg80Ni10Y10.
Their
crystallization
temperatures were determined by DSC
measurements, which displayed two andthree exothermic peaks for Mg90Ni5Y5 andMg80Ni10Y10, respectively. The crystallization
products were also examined by X-ray
diffraction. The microstructure was studied by
TEM and SEM. It was found that the as-spunribbons consists of an amorphous phase inwhich nanocrystalline Mg (Ni,Y) crystals (withan average size of 10 nm) are embedded in
the case of Mg90Ni5Y5 and a fully amorphous
structure for Mg80Ni10Y10. The hydriding
properties of the as-quenched and annealed
ribbons were studied using a magnetic
suspension balance, where reversible
gravimetric storage densities of 4 wt.-% H
were demonstrated.

Experimental
Mg90Ni5Y5 and Mg80Ni10Y10 alloys were
produced by melt spinning (surface velocityof 40 m/s) and characterized regarding theirmicrostructure, recrystallization behaviourand hydrogen storage properties using SEM,
TEM, XRD, DSC and TGA using a magnetic
suspension balance.

References[1] Gutfleisch et al; J. Alloys Compd. 413 (2005)
404[2] Spassov et al; J. Alloy Compd. 334 (2002) 219

Corresponding author: Siarhei Kalinichenka, email: Siarhei.Kalinichenka@ifam-dd.fraunhofer.de

94

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Magnesium by Gas Phase Condensation: morphology
microstructure and hydrogen sorption
E. Callini1, L. Pasquini1, A. Montone2, E. Piscopiello2, M. Vittori Antisari2 and E.
Bonetti1
1

Physics Department, University of Bologna, viale Berti-Pichat 6/2, 40127 Bologna, Italy

2

FIM Department, ENEA C. R. Casaccia C.P. 2400, 00123, Rome and C. R. Brindisi, via Appia
km 706, 72100 Brindisi, Italy
Inert gas condensation was employed to prepare nanoparticles of Mg and MgH2 which morphology,
clustering degree and structural stability have been investigated by X-ray diffraction and electron
microscopy. Thermodynamic functional properties of the Mg and MgH2 nanostructured samples were
investigated by Sievert apparatus and analysed in the framework of a simple sorption model.

Introduction
Several issues have been explored in lastyears in order to improve the kinetics ofhydrogen release by decomposition of MgH2,
mainly through tailored synthesis procedures
like ball milling and inert gas condensation(IGC) [1] and the addition of catalysts
particles. However basic aspects of MgH2Mg phase transformation are still underdiscussion [2] due to the lack of details on
the sample microstructure like the role ofparticles size or defects density [3]. We
analyse the behaviour of a simple model
system, i.e. Mg nanoparticles (NP) by IGC,
whose morphology consist of a single crystal
magnesium core surrounded by a thin MgOshell.

Experimental
For the synthesis by IGC, 99.8 % pure Mg
was sublimated in a helium gas atmosphere(2.50-250 Pa). Mg NP were collected on aliquid nitrogen cooled rotating cylinder andpassivated by exposure to oxygen controlled
atmosphere.
Transmission
electronmicroscopy observations were carried out
with a FEI Tecnai G2 30F microscope,equipped with a Schottky type field emission
source, operated at 300 kV. X-ray diffraction
was performed with a Rigaku DMAX IIIC
Bragg-Brentano apparatus using Cu-Kα

radiation. H-sorption functional properties
characterisation was achieved using a
Sievert type apparatus.

Results
Morphology and structure of the Mg NP
critically depend on some synthesis
parameters such as the gas pressure in thesynthesis chamber. The as synthesizedmaterial has been then submitted tocontrolled hydrogen ab-desorption cycles.
The experimental work is based on thecorrelation between kinetic properties,
evaluated in a volumetric Sievert apparatus,and microstructure, as derived from X-Ray
diffraction and TEM analysis. Different kinetic
behaviour for the adsorption and desorption
processes and the presence of activation
phenomena, fastening hydrogen
releaseand capture are discussed and interpreted in
the framework of a simple sorption model,
giving structural hints for better sorption
performances.

References[1] O. Friedrichs et al; J. Alloys Compd. 463(2008)[2] B.J. Kooi et al; Appl. Phys. Lett. 89 (2006)[3] A. Borgschulte et al; Appl. Surf. Sci. 254 (2008)

Corresponding author: Elsa Callini, email: elsa.callini@unibo.it, Tel. (+39) 051 2095298

95Braunwald, Switzerland 2009

Hydrogen Storage in Liquid Organic Hydrides
Katarzyna Morawa, S.C.Edman Tsang**, Anibal J. Ramirez-Cuesta *Wolfson Catalysis Centre, Inorganic Chemistry Laboratory, University of Oxford, OX1 3 QR UK*TOSCA, ISIS Facility, Rutherford Appleton Laboratory, Building R3, Chilton, Didcot, OX 11 0X
UK** Corresponding author
The hydrogenation of ethylcarbazole was studied in the melt conditions. Various catalytic systems were
tested and the reaction conditions were optimised. The path of the reaction was followed in the solvent, theintermediates were detected and characterised using GC-MS. The poor selectivity of ruthenium black incomparison to supported ruthenium was attributed to the different adsorption sites available on catalyst.

Introduction
An attractive way of storing hydrogen isusing liquid organic hydrides, which
utilize the reversible reactions ofhydrogenation and dehydrogenation ofaromatic
compoundssuch
asethylcarbazole.
In
this
work
the
hydrogenation of ethylcarbazole was studied
in the high pressure vessel in order tounderstand the reaction mechanism on
different catalytic systems.

be attributed to the formation of a stableintermediate. It is suspected that thereaction pathway may be dependant on
metal particle size.
Ru black[Plus0]2500
Conc(gr 2000pergr 1500
cat
aly
1000
st)

[Plus4][Plus6][Plus8][Plus12]
theory [Plus 0]
theory [Plus 4]
theory [Plus 6]500

theory [Plus 8]

Experimental0

theory [Plus 12]
0.0

5.0

10.0

15.0

20.0

25.0

30.0

time (hr)Ethylcarbazole was hydrogenated at 130°C
and of 70 bar hydrogen pressure. The results
were analyzed by GC-MS and HNMR.

[Plus0]45000
Conc (gr per gr catalyst)

Several different catalytic systems basedon noble metals and nickel have been
compared and the reaction conditions
were optimized. The reaction pathway of
ethylcarbazolehydrogenation
wasstudied using cyclohexane as a solvent.
Four different intermediates together with
their isomers were detected andidentified using GC-MS.

5 wt % Ru/ TiO2 red NaBH4

40000[Plus4]35000[Plus6]30000[Plus8]25000[Plus12]

20000

theory [Plus 0]

15000

theory [Plus 4]

10000

theory [Plus 6]

5000

theory [Plus 8]0

theory [Plus 12]
0.0

5.0

10.0

15.0

20.0

25.0

30.0

tim e (hr)Fig 1. Comparison of the reaction pathways ofruthenium black( top) and 5 wt% ruthenium supported
on rutile (bottom)

Results

Reference

Ruthenium was found to be the best
metal for the catalytic hydrogenation
studied. The difference in reaction
pathway was found between Ru blackand supported ruthenium (see Figure 1).
The poor selectivity of ruthenium black
towards fully hydrogenated product can[1] Hydrogen storage by reversible hydrogenationof pi-conjugated substrates Pez; Guido Peter(Allentown, PA)Scott; Aaron Raymond (Allentown,
PA) Cooper; Alan Charles (Macungie, PA) Cheng;
Hansong (Allentown, Patent no 7429372, Issued
30 Sept 200896

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009SCIENCE OF HYDROGEN & ENERGY AWARD
PROF. DR. JENS K. NØRSKOVThe “Science of Hydrogen & Energy” award is a price, just similar to the Nobel price, for an extraordinary
contribution to the sciences of hydrogen. The aim is to award a prize to a distinct scientist for his scientificwork of a life time.
Jens Nørskov was born on September 21 in1952. He received his Master degree in physics and chemistryfrom the University of Aarhus, Denmark in 1976 and his PhD in theoretical physics in 1979. During his PhD
he published papers about the electronic structure of H and He in metal vacancies and the contraction of
diatomic molecules upon chemisorption. Jens Nørskov was a Post Doc at IBM in Yorktown Heights, NewYork in 1979 and was affiliated with Nordita, (Nordic Institute for Theoretical Physics) in Copenhagen
before he became a member of the scientific staff of Haldor Topsøe A/S, Lyngby in 1981. He continued
the investigation of gas molecules at the surface of metals and developed a picture of adsorption anddesorption of hydrogen emerging from self-consistent model calculations.
In 1992 he was appointed as a professor of theoretical physics in the department of physics at theTechnical University of Denmark, Lyngby and became the director of the Center for Atomic-scale Materials
Physics (CAMP), Department of Physics, Technical University of Denmark, Lyngby. Recent research of
the group of Jens Nørskov covers several of the most relevant topics: 1) The development of theoreticalmethods e.g. “Scaling Properties of Adsorption Energies for Hydrogen-Containing Molecules on
Transition-Metal Surfaces”; 2) Theoretical surface science e.g. “Role of strain and ligand effects in themodification of the electronic and chemical properties of bimetallic surfaces”; 3) Nanostructures andmaterials properties e.g. “Atomic-scale imaging of carbon nanofiber growth”; 4) Heterogeneous catalysis
e.g. “Ammonia synthesis from first principles calculations”; 5) Biomolecules e.g. “Biomimetic hydrogen
evolution”; 6) Electrochemistry and fuel cells e.g. “The origin of the overpotential for oxygen reduction at afuel cell cathode”; 7) Hydrogen storage e.g. “Metal ammine complexes for hydrogen storage”
Jens Nørskov is not only a creative and brilliant scientist; he also belongs to the few scientists able tosuccessfully combine theoretical approches with experimental observations for the understanding of thebasic phenomena. It is always a great pleasure to listen to Jens Nørskovs talks, which are exciting eye
opening stories combined with some great new stimulating ideas.
For his enormous contribution in hydrogen sciences Jens Nørskov is awarded with the “Science ofHydrogen & Energy” price 2009. Congratulations!

97

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009SCIENCE OF HYDROGEN & ENERGY AWARD
DR. GARY SANDROCK

The “Science of Hydrogen & Energy” award is a price, just similar to the Nobel price, for an extraordinary
contribution to the sciences of hydrogen. The aim is to award a prize to a distinct scientist for his scientificwork of a life time.
Gary Sandrock received his master from the Institute of Technology, Cleveland in 1965 and his Ph.D. fromthe Western Reserve University, Cleveland in 1971. He worked from 1962-1969 as a research metallurgist
in the NASA Lewis Research Center, Cleveland, Ohio. From 1971-1983 he was Section Manager ofEnergy Systems at Inco Research and Development Center, Suffern, NY. From 1983-1991 he was Vice
President and Director of Technology at Ergenics, Inc., Ringwood, NJ. From 1992-1993 Gary Sandrock
was visiting professor at the Kogakuin University, Hachioji, Tokyo, Japan where he developed a newchemical surface treatment and investigated the activation characteristics of chemical treated AB5 alloys.
Gary then became the president of SunaTech, Inc., Ringwood, NJ, where he developed reversiblehydrogen storage systems. At the same time Gary Operating Agent, International Energy Agency
Hydrogen Implementing agreement Tasks 12 & 17 (Hydrogen Storage Materials) and worked as aconsultant for the US DOE via Sandia National Laboratories, Livermore, CA. In 1995 Gary Sandrock
started to creat and mainten Hydride Databases of IEA(HIA)/DOE/SNL (http://hydpark.ca.sandia.gov) andhe is author of several book chapters and review papers e.g. “A panoramic overview of hydrogen storage
alloys from a gas reaction point of view”. His recent research concentrates on the catalysis of the hydrogen
desorption from alanates and most recently Gary investigated the hydrogen desorption behavior of AlH3and explaned the mechanism of the kinetic stabilisation of aluminumhydrid. Furthermore, he published apaper entitled “Accelerated thermal decomposition of AlH3 for hydrogen-fueled vehicles” where he shows
the possible ways to change the activation barrier for the hydrogen desorption in a controlled way.
Gary Sandrock not only made significant achievements in understanding metal hydrides he also built thebridge from sciences to application. Furthermore, his scientific review papers and the hydride database are
inestimably value for the hydride society. Therefore, Gary Sandrock is awarded with the “Science ofHydrogen & Energy” price 2009. Congratulations!

98

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009PARTICIPANTS

99

3rd Hydrogen & Energy Symposium

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Agresti Filippo

University of Padova
Department of mechanical engeneering
via Marzolo, 9
IT-I35131 Padova

email: filippo.agresti@unipd.it
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Argun Hidayet

Dokuz Eylül University Env. Eng. Dpt.
Environmental Engineering
Buca Týnaztepe Campus
TR-35160 Ýzmir

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Tel: (+90) 0539 294 12 64
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Berke Heinz Prof. Dr.

Universität Zürich
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Bonatto Minella Christian

GKSS Research Centre Geesthacht
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Empa
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Bowman Robert Dr.

RCB Hydrides, LLC

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EPFL
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University of Twente
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University of Twente
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Callini Elsa

University of Bologna
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University Leiden
Leiden Institute of Chemistry
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CNRS
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ISIS Facility,
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Deprez Emilie

ICMSE
Nanostructure and nanostructured materials
Avenida Americo Vespucio 49
ES-41092 Sevilla

Dolci Francesco Dr.

Institute for Nanotechnology-Forschungszentrum email: francesco.dolci@int.fzk.de
KarlsruheTel: (+49) 7247 82 8910
Postfach 3640
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Domenech-Ferrer Roger

GNaM-UAB
campus UAB
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El Kharbachi Abdelouahab

NPG
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Er Suleyman

TWENTE UNIVERSITY
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GNaM-UAB
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Garroni Sebastiano

Universitat Autonoma de Barcelona
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Gebert FlorianTechnische Universität Braunschweig

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University of Düsseldorf
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Griessen Ronald Prof. Dr.

Vrije Universiteit Amsterdam
Physics
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NL-1081 HV Amsterdam

email: griessen@nat.vu.nl
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Grzeczka Grzegorz Dr.

Polish Naval Academy
Institute of Electrical Engineering and Automatics
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PL-81-103 Gdynia

email: g.grzeczka@amw.gdynia.pl
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Hagemann Hans Prof. Dr.

University of Geneva
Physical Chemistry30, quai E. Ansermet
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email: hansrudolf.hagemann@unige.ch
Tel:
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Hauback Bjørn C. Prof. Dr.

Institute for Energy Technology
Physics Department
P.O. Box 40
NO-2027 Kjeller

email: bjorn.hauback@ife.noTel: (+47) 63 80 60 78
Fax: (+47) 63 81 09 20

Jensen Jens Oluf Dr.

Technical University of Denmark
Department of Chemistry
Kemitorvet 207
DK-2800 Lyngby

email: joj@kemi.dtu.dk
Tel: (+45) 45 25 23 14
Fax: (+45) 45 88 31 36

Johansson Martin

Technical University of Denmark
Institute of Physics
CINF, Bld. 312
DK-2800 Lyngby

email:
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Tel: (+45) 45253191
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Kalinichenka Siarhei

TU Dresden
Wasserstofftechnologie
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DE-1069 Dresden

email: Siarhei.Kalinichenka@ifamdd.fraunhofer.de
Tel: (+49) (0) 351 2537 393
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Kasemo Bengt Prof. Dr.

Chalmers University
Applied Physics
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email: kasemo@chalmers.se
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Kato Shunsuke

Empa
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email: shunsuke.kato@empa.ch
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Kezar Charles Prof. Dr.

Lyndon State College
Business - Mathpo Box 129 Morgan, VT, USA
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email: ckezar34@aol.com
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Khandelwal Ashish Dr.

University of Padova
Department of Mechanical Engineering
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email: ashish.khandelwal@unipd.it
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Kollin Thomas

University of Aarhus
Department of Chemistry and iNano
Langelandsgade 140
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Konstanchuk Irina Dr.

Institute of Solid state Chemistry

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Krystian Maciej Dr.

Austrian Research Centers GmbH - ARC
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AGH - University of Science and Technology
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Leardini Fabrice Dr.

Universidad Autonoma de Madrid
Dpto. Fisica de Materiales
Av. Francisco Tomas y Valiente, 7
ES-28049 Madrid

email: fabrice.leardini@uam.es
Tel: (+34) 914974777
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Lodziana Zbigniew Dr.

EMPA
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Malecki Józef Dr.

Polish Naval Academy
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Smidowicza 69
PL-81-103 Gdynia

email: j.malecki@amw.gdynia.pl
Tel: (+48) 586262567
Fax: (+48) 586253881

Marashdeh Ali Dr.

Delft University of Technology
Materials Science and Engineering
Mekelweg 2
NL-2628 CD Delftemail:
A.A.M.AlMarashdeh@tudelft.nl
Tel: (+31) (0) 152782199
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Marinha Daniel

Grenoble Institute of Technology
LEPMI
1130, rue de la piscine
FR-38402 Saint Martin D'Hères

email: marinhad@lepmi.inpg.fr
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Maronsson Jon Bergmann
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Martelli Pascal

EMPA
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Matsumoto Mitsuru Dr.

Toyota Central R&D Labs., Inc.

email: e1345@mosk.tytlabs.co.jp
Tel: (+81) 561 71 7263
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Nagakute
JP-480-1192 Aichi
Mauron Philippe Dr.

EMPA
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email: philippe.mauron@empa.ch
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Milanese Chiara Dr.

University of Pavia
Physical Chemistry
Viale Taramelli, 16
IT-27100 Pavia

email: milanese@matsci.unipv.it
Tel: (+39) 0382 987670
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Morawa Katarzyna

University of Oxford
Inorganic Chemistry Department
South Park Road
GB-OX1 3QR Oxford

email:
katarzyna.morawa@linacre.ox.ac.
uk
Tel:Morrell Jonathan Dr.

Y-12 National Security Complex
Compatibility and Surveillance
1 Bear Creek Rd., MS #8097
US-37831 Oak Ridge

email: morrelljs@y12.doe.gov
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Muller Jiri Dr.

IFE
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Naujoks Nicola Dr.

Chalmers University of Technology
Applied Physics
Fysikgränd 3
SE-412 96 Göteborg

email: naujoks@chalmers.se
Tel: (+46) (0) 31 772 3331
Fax:

Nørskov Jens K. Prof. Dr.

Technical University of Denmark
CAMD
Fysikvej, Building 311
DK-2800 Kgs. Lyngby

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3rd Hydrogen & Energy Symposium
Palumbo Mauro Dr.

National Institute for Materials Science
1-2-1 Sengen
JP-305-0047 Tsukuba, Ibaraki

Braunwald, Switzerland 2009
email:PALUMBO.mauro@nims.go.jp
Tel:
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Pendolino Flavio

EMPA
Hydrogen & Energy
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Pistidda Claudio

FZK
INT
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Pottmaier Daphiny Dr.

COSY
UNITO
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email: daphiny.pottmaier@unito.it
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Proch Sebastian Dr.

Universität Konstanz
Clusterphysik
Universitätsstrasse 10
DE-78457 Konstanz

email:
sebastian.proch@unikonstanz.de
Tel: (+49) (0) 7531/882155
Fax: (+49) (0) 7531/885133

Ramirez-Cuesta Anibal Dr.

STFC
ISIS
Room 1-42
GB-OX11 0QX Chilton

email:
timmy.ramirezcuesta@stfc.ac.uk
Tel: (+44) 7787105335
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Remhof Arndt Dr.

Empa
Hydrogen and EnergyÜberlandstrasse 129
CH-8600 Dübendorf

email: arndt.remhof@empa.ch
Tel: (+41) (44) 823 4369
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Rodal Michael Dr.

Q-Senseemail: rodal@q-sense.com
Tel: (+46) 70 579 8053
Fax: (+46) 31 698 040

Hangpilsgatan 5
SE-426 77 V Frolunda
Rongeat Carine

IFW Dresden
Institute for Metallic Materials
Helmholtzstrsse 20
DE-1069 Dresden

email: c.rongeat@ifw-dresden.de
Tel: (+49) 351 4659 669
Fax: (+49) 351 4659 537

Sahara Ryoji

TU Delft
Dept of MSE

email: R.Sahara@tudelft.nl
Tel:
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NL- Delft
Sandrock Gary Dr.

Metal Hydride Technology
810 Hacienda Ave.
US-95616 Davis, CA

Schlag Stefan Dr.

SRI-Consulting / Access Intelligence Intl. LLC
Alfred Escher Strasse 34
CH-8002 Zürich

email:
gary.sandrock@sbcglobal.net
Tel: (+1) 530 753 0451
Fax:
email: sschlag@sric.ch
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Schmidt Thomas Dr.

Fraunhofer IFAM
Hydrogen Technology
Winterbergstr. 28
DE-1277 Dresden

email:
thomas.schmidt@ifamdd.fraunhofer.de
Tel: (+49) 351 2537413
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Schoenes Joachim Prof. Dr.

Technische Universität Braunschweig
Institut für Physik der Kondensierten Materie
Mendelssohnstrasse 3
DE-38106 Braunschweig

email: j.schoenes@tu-bs.de
Tel: (+49) 531 391 5130
Fax: (+49) 531 391 5155

Sikora Wieslawa Prof. Dr.

AGH-University of Science and Technology
email: sikora@novell.ftj.agh.edu.pl
Faculty of Physics and Applied Computer Science Tel: (+48) 12 617 38 50
Al. Mickiewicza 30
Fax: (+48) 12 634 00 10
PL-30-059 Krakow

104

3rd Hydrogen & Energy Symposium

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Sivula Kevin Dr.

EPFL
LPI
Station 6 (Bât. CH)
CH-1015 Lausanneemail: kevin.sivula@epfl.ch
Tel: (+41) (21) 693 36 69
Fax:

Stowe Ashley Dr.

B&W Y-12 NSC
Technology Development
PO Box 2009 MS 8097
US-37831 Oak Ridge

email: stoweac@y12.doe.gov
Tel: (+1) 865 241 0675
Fax:

Suleimanov Nail Prof. Dr.

Kazan Physical-Technical Institute
Novel Materials
Sibirsky Trakt, 10/7
RU-420029 Kazan

email: suleiman@kfti.knc.ru
Tel: (+7) 843 2319123(add.5)
Fax: (+7) 843 2725075

Szymak Piotr Dr.

Polish Naval Academy
Institute of Electrical Engineering and Automatics
Smidowicza 69
PL-81-103 Gdynia

email: p.szymak@amw.gdynia.pl
Tel: (+48) 586262881
Fax: (+48) 586253881

Tekin Adem Dr.

DTU
Physics
Building 307
DK-2800 Lyngby

email: tekin@fysik.dtu.dk
Tel: (+45) 4525 3184
Fax:

Vittori Antisari Marco Dr.

ENEA
Physical technologies and materials
Via Anguillarese 301
IT-123 Romeemail: vittori@casaccia.enea.it
Tel: (+39) 0630483119
Fax: (+39) 0639483176

Vogt Ulrich Dr.

EMPA
Abt. Hydrogen & Energy
Ueberlandstr. 129
CH-8600 Duebendorf

email: ulrich.vogt@empa.ch
Tel: (+41) (44) 823 4160
Fax: (+41) (44) 823 6244

Wiedenmann Daniel

Empa
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Duebendorf

email:
daniel.wiedenmann@empa.ch
Tel: (+41) (44) 823 4862
Fax:

Wirth Emmanuel Dr.

Setaram Instrumentation

email:
emmanuel.wirth@setaram.com
Tel: (+33) 472102588
Fax:

7 rue de l'oratoire
FR-69300 Caluire
Zakaznova Valentina Dr.

Empa
Abt. Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Zuerichemail: valentina.herzog@empa.ch
Tel: (+41) (44) 823 43 52
Fax: (+41) (44) 823 4022

Züttel Andreas Prof. Dr.

Empa
Abt. Hydrogen & EnergyÜberlandstrasse 129
CH-8600 Dübendorf

email: andreas.zuettel@empa.ch
Tel: (+41) (44) 823 4038
Fax: (+41) (44) 823 4022

105

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Braunwald, Switzerland 2009

Information

106

3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

Braunwald is car-free and only reachable by train (funicular railway). The latest departure timein Zürich airport is 20:51 to reach Braunwald on the same day. Please use the following website
for train connections:
http://www.sbb.ch/en/index.htm

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Braunwald, Switzerland 2009

EMERGENCY TELEPHONE NUMBERS
POLICE

117

FIRE FIGHTERS

118

AMBULANCE144

AMBULANCE HELICOPTER

1414

Corinne Gianola

076 398 9985

Andreas Züttel

079 215 4601

Hotel Alpenblick Reception

055 653 54 55

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3rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

BRAUNWALD

109

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Braunwald, Switzerland 2009

Braunwald Region

1103rd Hydrogen & Energy Symposium

Braunwald, Switzerland 2009

NOTES

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Braunwald, Switzerland 2009113

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Braunwald, Switzerland 2009114

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Braunwald, Switzerland 2009116