2nd Hydrogen & Energy Symposium

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Braunwald, Switzerland 2008

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

The 2nd symposium “Hydrogen & Energy” is the follows the successful inaugural symposium in February
2007 at Empa. It serves as an information platform of the fundamental science and the frontiers of
research in Sciences and Technology of 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 120.

21. - 25. January 2008

Hotel Alpenblick
CH-8784 Braunwald
Tel 055 643 15 44
URL: http://www.alpenblick-braunwald.ch
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CONTENTS
Timetable
MondayTuesday
WednesdayThursdayFridayAbstracts
Prof. Dr. Louis Schlapbach (inv. lec.)
History of Hydrogen
Prof. Dr. Ib Chorkendorff (inv. lec.)
Identification of Reactive Site for Design of New Materials for Hydrogen Production
Prof. Dr. Peter Notten (inv. talk)
Destabilized Fluorite-Structured Mg-Based Hydrogen Storage Materials
Mr. Jochen Linssen (talk)
Large Scale Production of Hydrogen? Carbon Capture and Storage as Option?
Prof. Dr. Aldo Steinfeld (talk)Solar Thermochemical Production of Hydrogen via H2O-splitting Cycles and Decarbonization
Processes
Dr. Roel Van de Krol (talk)
Deep Donor States in InVO4 Photo-Anodes for Solar Hydrogen Production
Dr. Elli Varkaraki (talk)
Performance of the RES2H2 Wind Hydrogen Plant in Greece
Dr. Alvaro Valdes de Luxan (talk)Oxidation and Photo-oxidation of Water on the Rutile TiO2 (110) Surface
Prof. Dr. Shin-Ichi Orimo (inv. lec.)
Metal Borohydrides for Energy Applications
Dr. Maximilian Fichtner (inv. lec.)
Challenges in the Development of Complex Hydride Based Systems for Reversible Hydrogen
Storage

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Mr. Christoph Langhammer (talk)Hydrogen Storage in Metal Nanoparticles: A Novel Nanoplasmonic Hydrogen Sensing Scheme
Prof. Dr. Cor Peters (talk)
Novel Results in Hydrogen Storage as Hydrogen Clathrate Hydrates
Prof. Dr. Joachim Schoenes (talk)Low Temperature Raman Spectroscopy of LiBH4 and LiBD4
Dr. Andreas Borgschulte (talk)Raman Spectroscopy to Probe Hydrogen-deuterium Exchange Reactions in Complex Hydrides
Dr. Arndt Remhof (talk)Monitoring the Synthesis of LIBH4 by In-situ Neutron Diffraction
Prof. Dr. Asuncion Fernandez Camacho (talk)Role of Nb2O5 Additives in the Hydrogen Sorption Kinetics of Nanocrystalline Mg
Dr. Michael Bielmann (talk)Flow-Pct Method for Characterization of Hydrogen Storage Materials
Prof. Dr. Hannes Jonsson (inv. lec.)
Calculations on Hydrogen in Nanoscale Metal Clusters
Dr. Tejs Vegge (inv. talk)
DFT Modelling of Novel Materials for Hydrogen Storage
Prof. Dr. Andreas Züttel (talk)About the Stability of Complex Hydrides
Dr. A.J. Ramirez-Cuesta (talk)
Thermodynamical Consideration in the Stability of Simple Alkali Metal Hydrides
Dr. Zbigniew Lodziana (talk)
May Titanium Be a Good Catalyst for LiBH4 Synthesis?
Dr. Riccarda Caputo (talk)Alkaline Metal-Boron Systems: First Principles Calculations
Dr. Jan Rossmeisl (inv. talk)
Oxygen Evolusion Reaction in Different Contexts
Prof. Dr. Peter Edwards (inv. lec.)
Lithium and Sodium Amidoboranes – New High Capacity Hydrogen Storage Materials
Dr. Bernard Dam (inv. talk)Hydrogenography: From Pd to Complex Metal Hydrides
Dr. Stefano Deledda (talk)Hydride Formation in Mechanically Activated Mg-Based Systems
Dr. Nobuko Hanada (talk)
Thermal Decomposition Steps of Mg(BH4)2 Under He Flow and H2 Pressure
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Dr. Philippe Mauron (talk)Stability and Reversibility of LiBH4
Mr. Florian Buchter (talk)
Crystal Structure of Ca[BD4]2
Dr. Martin Steinbacher (talk)Hydrogen in the atmosphereProf. Dr. Adriano Zecchina (inv. lec.)
The Vibrational Spectroscopy of Hydrogen Adsorbed on Microporous Systems
Prof. Dr. Michael Grätzel (inv. talk)Solar Hydrogen Generation from Water
Prof. Dr. Giovanni Principi (talk)Scaling up Effects of Mg Hydride as a Material for Hydrogen Storage
Ms. Doreen Thiele (talk)Combined Platinum/Perovskite Catalyst for an Efficient Nanostructured Air ElectrodeDr. Ronnie Vang (talk)
A Cu/Pt Near-Surface Alloy for Water-Gas Shift Catalysis Studied by STM, XPS, TPD, and DFT
Mr. Björn Wickman (talk)Thin-film Electrocatalysts for PEM Fuel Cells
Dr. Andras Tompos (talk)High-throughput and Componatorial Methods Used for Hydrogen Technologies. Design ofCatalysts for Production and Purification of Hydrogen
Prof. Dr. Dinko Chakarov (talk)
Photocatalytic Water Dissociation at Graphite/Ice Interface
Dr. Peter Schlinger (talk)
HY.MUVE – Hydrogen Driven Municipal Vevicle
Dr. Nicola Naujoks (poster)
Quartz Crystal Microbalance for Hydrogen Storage Messurements
Dr. Elisa Gil Bardaji (poster)
Thermal Properties of Mg(BH4)2 Doped with Transition Metal Chlorides
Mr Sebastiano Garroni (poster)
Improving RHC Compounds Preparation by Ball Milling
Ms Emilie Deprez (poster)
Microstructural and Chemical Study of 2LiBH4+MgH2 Reactive Hydride Composite for H2
Storage
Mr Shunsuke Kato (poster)
Mass Flow Method for the Characterization of Hydrogen Sorption Kinetics
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Mr Flavio Pendolino (poster)
ThermoGravimetry of Li[BH4]Mr Pascal Martelli (poster)
Stability of Na[BH4]
Dr. Llamas Jansa Isabel (poster)
Monitoring the Synthesis of LiBH4 and Mg(BH4)2 by Ball Milling Under Different Pressures andAtmospheres
Dr. Oliver Friedrichs (poster)
Li[BH4] and Li[BD4] synthesis from Li-B alloy
Mr. Jon Steinar Gardarsson Mydral (poster)
Theoretical Studies of Hydrogen in Nanoscale Al-Clusters
Prof. Kuznetsov Andrej (poster)

SCIENCE OF HYDROGEN & ENERGY AWARD
List of Participants
Information
Notes

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ABSTRACTS

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HISTORY OF HYDROGENLouis Schlapbach
Empa Materials Science and Technology, CH-8600 Dübendorf, Switzerland
1766 Cavendish reports hydrogen to be 7 to 11 times lighter than air
1783 Balloon made of paper and filled with 25 m3 hydrogen gas ascends to nearly 914 meters
1800 Nicholson and Carlisle separate water into oxygen and hydrogen by passing an electric current
through it
1820 Cecil carries out experiments using hydrogen as an engine fuel1839 Sir William Grove constructs a "gas voltaic battery" as the forerunner of modern fuel cells
1861 Kirchhoff and Bunsen analyze the emitted spectrum of the sun and find hydrogen to be the major
constituent of the sun1866 First dynamoelectric generator demonstrated, ends temporally the development of fuel cells aselectricity generators
1874 Jules Verne writes his novel "The Mysterious Island" in which water delivers energy
1898 James Dewar uses regenerative cooling to become the first to statically liquefy hydrogen
1898 Gmür starts the first industrial hydrogen production in Switzerland
1909 Fritz Haber discovers a process allowing the synthesis of ammonia (NH3) from the elements
hydogen and nitrogen
1911 Carl Bosch upscales Haber’s synthesis to industrial production scale
1937 The Hindenburg disaster in Lakehurst ends the air applications of hydrogen after 150 years
1955 Justi describs the utilization of hydrogen as an energy carrier
1957 Lift-off of a hydrogen-powered B-57 Canberra jet, showing the potential of hydrogen as aviation fuel1959 First fuel cell vehicule equipped with alkaline fuel cells delivering a power of 15kW demonstrated
1959 Zdansky, on behalf of LONZA, files a patent on a pressured electrolysis system
1963 Rockets are launched using liquid hydrogen and oxygen as propellent
1967 Saturn V rocket lifts off with 12'000 m3 of liquid hydrogen
1967 GM’s Electrovan is the first operational fuel cell powered electric vehicle
1969 A hydrogen energy concept using properties of hydrogen including non-conventional energy
systems developed
1970 Kordesch builds an alkaline fuel cell/battery hybrid electric car based on an A-40 Austin sedan anddrives it for three years
1974 The first hydrogen vehicle in Japan is a small pick-up Musashi 1 equipped with an internal
combustion engine
1984 Daimler-Benz together with Aral, Dornier, Mannesmann, Thyssen Engineering
demonstrates the Mercedes 280 TE hybrid vehicule equipped with a gasoline and hydrogen internal
combustion engine
1988 A triple-jet powered Tupolew Tu-154 flies with a liquid hydrogen fueled engine
1988 The 10 Daimler-Benz vehicles in operation since 1984 ran more than 250'000 km
1993 Uni Geneva presents a hydrogen powered Lawn Mower
1994 Based on a Mercedes-Benz transporter MB-180, NeCar 1 demonstrates 50kW fuel cell combinedwith a 30 kW electric drive
1998 The EU launches CUTE, Clean Urban Transport for Europe
1998 First Hydroxy demo project with 100 W fuel cell for transportation on water
2000 Total hydrogen production worldwide amounts to 500 bn m3 (STP) or approximately 45 mio tonnes
annually
2001 BMW demonstrats a small fleet of 15 vehicles with hydrogen-powered internal combustion engines
2002 A small series of Daimler Chrysler A-class cars called F-Cell is produced. A 85 kW Mark 902 fuelcell and a compressed hydrogen tank at 350 bar allows range of 150 km

Corresponding author: Louis Schlapbach, email: louis.schlapbach@empa.ch, Tel. (+41) (44) 823 4500

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IDENTIFICATION OF REACTIVE SITE FOR DESIGN OF NEW
MATERIALS FOR HYDROGEN PRODUCTION
Ib Chorkendorff
NanoDTU, Department of Physics, Technical University of Denmark, DK-2800 Lyngby
As fossil fuel reserves become depleted in the future, alternative energy carriers such as H2 may become
more prominent. H2 can easily be produced from fossil fuels and can be a primer for a later sustainable andclean production from solar or wind energy if those are coupled to water electrolysis. Unfortunately, thehydrogen evolution reaction is catalyzed most effectively by Pt-group metals which are scarce andexpensive. If this scheme is to become viable, new materials are needed. The importance of identifying theactive sites is discussed with respect to make new materials both with respect to electro-catalysis but also
conventional catalysis.

Results
In the first I will focus on developing new
structured electro-catalysis materials forhydrogen evolution by electrolysis. It will beshown how Pt can be modified by lessexpensive metals to introduce surface alloys
with new properties. Here 736 different
systems were ranked theoretically by DFT
taking not only reactivity, but also the stability
towards phase separation and corrosion into
account. We have subsequently tested themost promising candidate, the Bi-Pt surface
alloy toward the Hydrogen evolution reaction
and found it being improved compared to thestandard Pt electrode material [1]. In thesecond part, new materials inspired bybiomimetics will be discussed and it will bedemonstrated how the detailed atomic
structure, measured by STM, and thehydrogen evolution reaction on MoS2 clusters
can be used to identify the reactive site on
the edge of the particles [2, 3]. Possibilities
for further enhancement of this effect will be
discussedand
illustratedbysome
preliminary examples.
If time allows the importance of identifying
the active site and the possibilities forenhancing and improving the conventional
catalytic methods for hydrogen production
through processes related through the steam
reforming process [4] will be discussed. Herewe will demonstrate on extended single

crystals that the detailed atomic structure on
the surface has a great potential forenhancing the reactivity of the nanoparticles,
if we can control the presence of the reactive
centers [5].

Figure 1 showing the volcano behavior of theexchangecurrent
andthepositionofnanoparticulate MoS2 shown as an insert.

References
[1]
[2]
[3]
[4]
[5]

J. Greeley, et al., Nature Materials 5 (2006)
909.
B. Hinneman et al., JACS 127 (2005) 5308.
T.F. Jaramillo et al., Science 137 (2007) 100.
F. Abilgaard-Pedersen et al., Surf. Sci. 590(2005) 127.
M. P. Andersson et al. Submitted J. Catal.
(2007).

Corresponding author: Ib Chorkendorff, email: ibchork@fysik.dtu.dk, Tel. (+45) 4525 3170

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SOLAR HYDROGEN GENERATION FROM WATER
Michael Grätzel
Laboratory of Photonics and Interfaces, Ecole Polytechnique Fédérale de Lausanne, CH-1015
Lausanne, Switzerland
Silicon-doped α-Fe2O3 exhibiting a cauliflower-type nanostructure was prepared by atmospheric pressurechemical vapor decomposition. When used in conjunction with surface adsorbed Co(II) ions to promotewater oxidation to oxygen photocurrents up to 2.8 mA/cm2 was obtained, corresponding to a solar tochemical conversion efficiency of 4.2% in a tandem cell.

Introduction

Results

The cleavage of water into hydrogen andoxygen by visible light remains the Holy Grailof current photochemical research [1]. In
contrast to the “brute-force” approach using
photovoltaic panels to electrolyze water,these systems employ semiconductor films
or particles, which are able to perform themulti-electron transfer reactions involved in
the water oxidation and reduction process.
Iron oxide (a-Fe2O3, or hematite) is especiallyattractive as a photo-anode due to its
abundance, stability and environmental
compatibility, as well as suitable band gap
and valence band edge position. However,
the reported efficiencies of water oxidation at
illuminatedhematiteelectrodes
arenotoriously low. This lecture reports on theuse of mesoscopic hematite films that showpromising performance as photoanode in atandem cell that accomplishes the splitting ofwater by visible light.

When used in conjunction with surface
adsorbed Co(II) ions to promote wateroxidation to oxygen photocurrents up 2.8
mA/cm2 was obtained. This corresponds toan overall solar to chemical conversion
efficiency of 4.2 % in a tandem device usinga dye sensitized solar cell as a bottom
electrode [3]. The incident photon to wateroxidation conversion efficiency reaches 50
percent at 380 nm, the photoactivity of thefilms extending far into the visible beyond
600 nm. A mechanistic model for waterphotooxidation is presented, involving
stepwise accumulation of four holes by two
vicinal iron or cobalt surface sites.

Experimental
We have deposited nano-structured α-Fe2O3
films on F-doped SnO2 glass substrates byultrasonic spray pyrolysis (USP) andchemical vapor deposition at atmosphericpressure (APCVD). The most efficient photoanodes were obtained with silicon doped
hematite films prepared by APCVD. Apartfrom rendering the films conductive thesilicon doping strongly influenced By themesoscopic film morphology [2]. The silicondoped α-Fe2O3 exhibits a cauliflower-type
nanostructure as shown in Figure 1 below.

Figure 1. Scanning electron microscopy picture ofa silicon doped hematite film supported on fluorine
doped tin dioxide(FTO) conducting glass. Note thecauliflower-type nanostructure obtained by
APCVD. The feature size is about 14 nm.

References
[1]
[2[
[3]

Graetzel, M. Nature 414 (2001), 338
Cesar, I. et.al; JACS 128 (2006), 4582.
Kay, A. et al; JACS 128 (2006) 15714.

Corresponding author: Michael Grätzel, email: michael.graetzel.@epfl.ch; Tel. (+41) (21) 693 3112
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LARGE SCALE PRODUCTION OF HYDROGEN – CARBONCAPTURE AND STORAGE AS OPTION?
Jochen Linssen, Jürgen-Friedrich Hake, Peter Markewitz, Dag Martinsen
Forschungszentrum Jülich GmbH, Institute of Energy Research - Systems Analysis andTechnology Evaluation, D-52425 Jülich, Germany
In view of the future vision of a “hydrogen economy”, gasifying coal and/ or reforming natural gas close tosuitable carbon dioxide storage options could be a possible interim solution to the long-term goal ofemission-free hydrogen generation. The spatial separation of electricity generation into fossil hydrogenproduction with CO2 capture and dispersed hydrogen-fueled electricity generation has the advantage ofzero emission power generation near to consumers (apart from CO2 also other air pollutants). The
construction of an adequate infrastructure would be necessary for this proposed path.

Introduction

Analysis

The location of hydrogen production plants incombination with decoupled electricity
generation and the necessary infrastructure
are important aspects. In the past, essential
criteria for conventional fossil electricity
generation were proximity to consumers aswell as the location-bound availability ofenergy carriers. Transport routes have to be
kept short in order to avoid losses and thus
additional costs. For conceivable fossilhydrogen production with CO2 capture theexistence of storage options will play a keyrole for plant siting. As a rule, carbon dioxide
storage options are not located near existing
power plants or exploration sites so possibly
new power plant locations must be taken into
account.

The focus of the contribution will be theanalysis of potential fossil hydrogengeneration options with CO2 capture, suitablestorage options and the resulting energy
transport tasks for decoupled hydrogen/electricity generation. Different gasification/
reforming options with CO2 capture and theresulting hydrogen generation costs will be
described and estimated. The contribution
identifies promising technologies and costtrends for the next two decades. The
technology and cost analyses especiallyhighlight the requirements of the new
infrastructure (e.g. CO2 or H2 pipelines) bymeans of scenario considerations. Stranded
investments could be avoided by also using
this infrastructure for the long-term shift tohydrogen economy. The analysis will focus inparticular on the German energy system.

Corresponding author: Jochen Linssen, email: j.linssen@fz-juelich.de, Tel. (+49) 2461 61 3581

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SOLAR THERMOCHEMICAL PRODUCTION OF HYDROGEN VIA
H2O-SPLITTING CYCLES AND DECARBONIZATION PROCESSES
Aldo Steinfeld
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland andSolar Technology Laboratory, Paul Scherrer Institute, 5232 Villigen, Switzerland
Solar thermochemical processes for the production of fuels make use of concentrated solar radiation as
the energy source of high-temperature process heat. Considered are water-splitting thermochemical
cycles based on metal oxide redox reactions at above 2000 K, and reforming/gasification/decomposition
processes for the thermal decarbonization of fossil fuels at above 1500 K. A Second-Law analysis
indicates the inherent thermodynamic advantage for efficiently storing intermittent solar energy into
chemical fuels via high-temperature endothermic processes, and the potential of avoiding greenhouse gas
emissions and other pollutants in the production of hydrogen, syngas, and other synthetic fuels.
The research work encompasses fundamental studies on chemical reactor engineering, with emphasis on
the analysis of radiation heat transfer in gas-solid reacting flows. Solar reactor prototypes are designed,
fabricated, modeled, and tested in a high-flux solar furnace, and further optimized for maximum solar-tochemical energy conversion efficiency.

Corresponding author: Aldo Steinfeld, email: aldo.steinfeld@eth.ch, Tel. (+41) (44) 632 7929

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DEEP DONOR STATES IN InVO4 PHOTO-ANODES FOR SOLAR
HYDROGEN PRODUCTION
Roel van de Krol and Cristina S. Enache
Delft University of Technology, Faculty of Applied Sciences, Department DelftChemTech,
Julianalaan 136, 2628 BL Delft, The Netherlands
Recent work on InVO4 photo-catalyst powders suggests that this may be a promising photo-anode material
for solar water splitting. Thin films of InVO4 were deposited by spray pyrolysis, and their optical andelectrochemical properties were investigated. Electrochemical impedance analysis reveals a highconcentration of deep donors in the material. In contrast to earlier reports, the visible light photo-responseof this material appears to be caused by optical transitions to these deep donor levels, and not to an
intrinsically small bandgap.

Introduction
The direct conversion of solar energy intohydrogen represents an attractive but
challenging alternative for photovoltaic solar
cells. Several metal oxide semiconductors
are able to split water into hydrogen andoxygen upon illumination. While most of theresearch efforts so far have been focused on
binary oxides, such as (doped) TiO2 andFe2O3, the past few years have shown an
increasing interest in ternary and even more
complex metal oxides. When dispersed as apowder in an aqueous solution, several ofthese materials (e.g. InVO4, In1-xNixTaO4,
BiVO4, NaTaO3, etc.) can evolve oxygen
and/or hydrogen. However, with typicalevolution rates of 1 to 100 µmole.g-1.h-1,
efficiencies are still too low for practicalapplications. To investigate the relevantmaterials properties of InVO4 in more detail,thin dense films were made by spraypyrolysis, and investigated by optical andelectrochemical techniques.

Results
The optical absorption spectra reveal a
bandgap of 3.2 eV, which seems tocontradict earlier reports on visible lightabsorption by InVO4 powders (Ye et al.,Chem. Phys. Lett. 356 (2002) 221). A
detailed electrochemical impedance study

reveals a high donor density (6×1019 cm-3)
and a very low conductivity (∼3×10-8 Ω-1cm-1).
These observations can be rationalized by
the presence of deep donors in the material.

Fig. 1. SEM image of the InVO4 film (left), andproposed energy diagram indicating the presenceof optically active deep donors.

The presence of ionized deep donors in thedepletion layer gives rise to an opticaltransition from the valence band to the donor
level, and we believe that this transition is
responsible for the visible light photo-activityof InVO4 powders. At the same time, thesedeep defects may also act as recombination
centers. This illustrates the important, but
often underestimated role of ionic defects on
the performance of novel photo-catalysts
based on complex oxides.

Corresponding author: Roel van de Krol, email: r.vandekrol@tudelft.nl, Tel. (+31) (15) 278 2659

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PERFORMANCE OF THE RES2H2 WIND-HYDROGEN PLANT IN
GREECE
Elli Varkaraki, George Tzamalis, Emmanuel Zoulias, Emmanuel Stamatakis
Centre for Renewable Energy Sources, RES & Hydrogen Technologies Section, 19th km.
Marathonos Av., 19009 Pikermi Attikis, Greece
The wind-hydrogen plant of the Centre for Renewable Energy Sources in Keratea, Greece has been in
operation for over two years now. It is composed of a 25 kW alkaline electrolyser, a single-stage hydrogencompressor with filling station at 0.22 MPa, and metal hydride tanks with a LaNi5-based alloy for the
storage of 3.7 kg hydrogen, all connected to a 500 kW wind turbine. The performance of the plant has
been studied under static and dynamic conditions, according to different operational modes. The charging
and discharging characteristics of three metal hydride tanks, supplied with electrolytic hydrogen without
purification, will be discussed.

Introduction
There are less than a dozen wind-hydrogendemonstration plants in operation worldwide,
presenting important differences, either
regarding their components, or their control
strategy. The lessons learned from thedesign, construction and operation of suchplants are valuable, because the components
and interfaces are far from optimized. The
wind-hydrogen plant in the wind farm of
CRES in Keratea, was constructed in thecontext of the FP5 European projectRES2H2 (ENK5-CT2001-536), and operation
started in October 2005.

temperature of the electrolyser, without
further purification, will also be presented.
Metal hydride tanks are suitable for windhydrogen storage under particular conditions
and mainly if hot water is available at an
adequate temperature, in order to avoid theuse of an electrical boiler. Their control in
integrated systems is particularly delicate.
An example of the pressure and watertemperature evolution during the preheating
and discharging of three metal hydride tanks
is shown in the figure below.

Results
The electrolysis stack has not been protectedby cathodic polarization during these twoyears of operation, in order to test thecorrosion resistance of the activatedelectrodes, which seems very satisfactory.
The electrolyser performance under variable
power input will be discussed.
The operation of the metal hydride tanks
charged with electrolytic hydrogen containing
around 0.2%v. oxygen and saturated withhumidity at the operating pressure andFig. 1. Discharge of metal hydride tanks.

Corresponding author: Elli Varkaraki, email: evarkara@cres.gr, Tel. (+30) (210) 660 3397

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Braunwald, Switzerland 2008OXIDATION AND PHOTO-OXIDATION OF WATER ON THE RUTILE
TiO2 (110) SURFACE
Á. Valdés1, Z.-W. Qu1, G.-J. Kroes1, J. Rossmeisl2, J.K. Nørskov2
1

Leiden Institute of Chemistry, Gorlaeus Laboratory, Leiden University, P.O. Box 9502, 2300
RA, Leiden, The Netherlands
2

Center for Atomic-scale materials Design, Department of Physics, nano-DTU, Technical
University of Denmark, 2800 Kgs. Lyngby, Denmark
A density functional theory (DFT) based method for computing the free energies of electrode / adsorbate /electrolyte systems [1] is generalised from electrolysis to photoelectrolysis. The oxidation and photooxidation of water on the rutile TiO2 (110) surface is investigated using DFT calculations.

We first study different oxygen coverages ofthe surface in contact with H2O and theirrelative stability as a function of the appliedbias and the pH of the electrolyte, and thenanalyze the reaction mechanisms of theoxidation of water on the surfaces that arestable over a particular range of bias andpHvalues,accordingtothethermochemistry of the reactions four
elementary electron transfer reactions, andanalyze the overpotential needed for theelectrolysis and photo-electrolysis of water.

We found that the most difficult step in the
splitting of water process is the reaction ofan H2O molecule with a vacancy in thesurface to form an adsorbed hydroxyl group(OH*). Comparison to experiment [2] showsthat the computed overpotential for O2
evolution (0.78 V) is available under theexperimental conditions required for bothoxygen and hydrogen evolution.

References[1][2]

J. Rossmeisl, A. Logadottir, and J.K.
Nørskov, Chem.Phys. 319, 178 (2005)
A.J. Nozik, Nature, 257, 383 (1975)

Corresponding author: Alvaro Valdes de Luxan, email: avdeluxan@chem.leidenuniv.nl, Tel. (+31) (71) 527
4533

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METAL BOROHYDRIDES FOR ENERGY APPLICATIONS
Shin-ichi Orimo, Yuko Nakamori, Hai-Wen Li, Toyoto Sato, Motoaki Matsuo
Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577, Japan
Various energy applications of metal borohydrides, such as high-density hydrogen storage, advanced
neutron shielding, microwave absorption, and lithium super-ionic conduction, will be introduced in thepresentation.

Development of hydrogen storage materials
is one of indispensable issues for hydrogenenergy applications [1-3]. Candidates for thematerials are metal borohydrides such as
LiBH4, Mg(BH4)2, Ca(BH4)2, Y(BH4)3 [4-8];
including their intermediate compounds [911].
The thermodynamical stabilities of a series ofmetal borohydrides (M(BH4)n with M = Li, Na,
K, Cu, Mg, Zn, Sc, Zr, and Hf; n = 1-4) weresystematically investigated by using both thefirst-principles studies and hydrogen desorption measurements [12]. The former
indicated that the charge transfer from themetal M (or cation Mn+) to the complex anion[BH4]– is a key feature for the stability ofM(BH4)n, and also that there exists a linear
relationship between the calculated heat offormation ∆H of M(BH4)n and the Paulingelectronegativity χP of M.
The hydrogen desorption temperature Td of
M(BH4)n determined using gas chromatography was also closely correlated with χP;that is, Td decreases with an increase in thevalue of χP. Therefore, the Pauling electronegativity χP of M is an good indicator for
appropriately producing/designing the metalborohydrides M(BH4)n for various hydrogenenergy applications.
Also, microwave irradiation effects on
selected metal borohydrides (LiBH4, NaBH4,
and KBH4) were investigated for the promotion of hydrogen desorption reactions [13, 14]
By microwave irradiation, LiBH4 was heated
rapidly above 380 K, at which almost allhydrogen was desorbed. The rapid heating of

LiBH4 is related to a structural transition fromorthorhombic to hexagonal at 388 K.
Recently, it was newly discovered that theelectrical conductivity of LiBH4 jumped bythree orders of magnitude due to thestructural transition [15]. The hexagonalphase above 388 K exhibited a high electricalconductivity of the order of 10−3 Scm−1. The
electrical conductivity in the hexagonal phaseis due to the Li super-ionic conduction. The
phenomena will lead to the developments of“solid-state hydride electrolytes” for highsafety lithium ion battery.

References[1][2]

Züttel, et al; Scripta Mater. 56 (2007) 823.
Dornheim, et al; Scripta Mater. 56 (2007)
841.
[3] Orimo, et al; Chem. Rev. 107 (2007) 4111.
[4] Li, et al; Scripta Mater. 57 (2007) 679.
[5] Miwa, et al; Phys. Rev. B 74 (2006) 155122.
[6] Bösenberg, et al; Acta Mater. 55 (2007)
3951.
[7] Sato, et al; Phys Rev. B, communicated.
[8] Buchter, et al; Phys Rev. B, communicated.
[9] Orimo, et al; Appl. Phys. Lett. 87 (2006)
021920.
[10] Ohba, et al; Phys. Rev. B 74 (2006) 075110.
[11] Li, et al; Acta Mater. in press.
[12] Nakamori, et al; Phys. Rev. B 74 (2006)
045126.
[13] Nakamori, et al; Appl. Phys. Lett. 88 (2006)
112104.
[14] Matsuo, et al; Appl. Phys. Lett. 90 (2007)
232907.
[15] Matsuo, et al; Appl. Phys. Lett. 91 (2007)
224103.

Corresponding author: Shin-ichi Orimo, email: orimo@imr.tohoku.ac.jp, Tel. (+81) 22 215 2093

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Braunwald, Switzerland 2008

CHALLENGES IN THE DEVELOPMENT OF COMPLEX HYDRIDEBASED SYSTEMS FOR REVERSIBLE HYDROGEN STORAGE
Maximilian Fichtner
Forschungszentrum Karlsruhe, Institute of Nanotechnology, P.O. Box 3640, D-76021 Karlsruhe
An overview will be given on complex hydride systems which are currently investigated for reversiblehydrogen storage. The state-of-the art will be presented for single compounds and combined systems.
Setbacks in the development will be outlined, and challenges and opportunities for the future will be
discussed.

Although the physical limits of solid storage
materials promise storage capacities which
are much higher than the conventional
storage methods only a few systems havebeen identified so far which have thepotential of meeting the international targets
for mobile hydrogen storage (see Fig. 1).

Fig. 1 Average H-H distances and volumetricstorage densities of gaseous (pressurized)hydrogen, liquid hydrogen, and the physical limitof hydrogen in a metal lattice according to theWestlake criterion [1].

Currently there is only one complex hydridecompound which seems to have potential tomeet the requirements of a technicalapplication [2,3]. Mg(BH4)2 has a high H
content of 14.9 wt.% H and thermodynamic
properties of a room temperature storage
material. However, first results indicate that
there are problems with the reversibility of
the compound at moderate conditions.

The concept of combined systems based ona solid state reaction between a complex
hydride and a binary hydride offers thepotential of achieving high capacities and low
working temperatures. However, not all of theseeminglyinteresting
reactionsarepracticable because a stepwise reaction may
lead to a situation where the calculated
overall thermodynamic parameters do notdescribe the real behaviour of the system [4].
Moreover, there are high kinetic barriers
involved in the transformations of such asystem. For higher reaction rates a fast andmobile species might be beneficial for thematerials transport. But, if such anintermediate is volatile at the operating
conditions, this may also be detrimental forthe fuel cell and the storage capacity in casethe species is desorbed together with thehydrogen.

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

Fichtner, M.; Scripta Materialia 56 (2007)
801
Matsunaga, T. et al.; J. Alloys Compd.
(2008) in press
Chlopek, K. et al.; J. Mater. Chem. 17 (2007)
3496.
Hanada N., Lohstroh W., Fichtner M.;
Comparison of the Calculated andExperimental Scenarios for Solid-State
Reactions Involving Ca(AlH4)2, J. Phys.
Chem. C (in press) DOI: 10.1021/jp074534z

Corresponding author: M. Fichtner, email: fichtner@int.fzk.de, Tel. (+49) (7247) 82 5340

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HYDROGEN STORAGE IN METAL NANOPARTICLES: A NOVELNANOPLASMONIC HYDROGEN SENSING SCHEME
Christoph Langhammer, Igor Zorić and Bengt Kasemo
Chalmers University of Technology, Department of Applied Physics, 412 96 Göteborg, Sweden

Introduction
Localized Surface Plasmon Resonances(LSPR) are collective excitations ofconduction electrons in a metal nanoparticle.
For an extended surface the surface plasmon
resonance energy is determined by theelectron structure. For a sufficiently small
particle (typically less than a few hundrednm) the plasmon energy depends also on theparticle size and shape as well as on its
dielectric environment. We have recently
systematically characterized the plasmonic
properties of supported nanodisk arrays ofthe transition metals Pt and Pd, fabricated byHole-Mask Colloidal Lithography [1], over alarge size and spectral range (UV-vis-NIR).
Spectrally tunable LSPR with cross sections
comparable to the “classic” plasmonic
materials Au and Ag were found [2].

as the change in extinction, wereapproximated by a linear dependence on thehydrogen content for the α, the α+β and theβ phase regimes, could successfully produce
p-C isotherms from the LSPR data [3]. The
agreement with literature for the bulk Pd-H
system is excellent. These results provide a
valuable novel experimental approach forstudying hydrogen storage materials andopen up a novel route towards ultra sensitive
optical hydrogen sensors.

Experimental
With Pd as model system, we demonstrate anovel plasmonic sensing principle, based on
the spectral shift caused by the change in thebulk electronic properties of the particle whena new atom (in this case hydrogen) enters
the lattice. Specifically, we use the LSPR asa very sensitive, non-destructive and realtime, remote optical probe to study hydrogenstorage in Pd nanodisks in solid solution (αphase) and metal hydride (ß-phase).

Results
Isotherms obeying Sievert’s law wereobserved in the α-phase region and a typicalhysteresis upon charging and discharging
with two plateau pressures of 18 torr and7.5torr, respectively, were observed for the
α+β phase coexistence region. A simple
model, where the spectral LSPR shift, as wellFig. 1: a) SEM micrograph and AFM scan of thestudied structures. b) Plasmonic response to H2.
c) Pressure-LSPR isotherm for 300nm Pd disks.

References[1] Fredriksson, et al; Adv. Mat. 19 (2007) 4297
[2] Langhammer, et al; Nano Lett. 6 (2006) 833[3] Langhammer, et al; Nano Lett. 7 (2007) 3122

Corresponding author: Christoph Langhammer, email: christoph.langhammer@fy.chalmers..se, Tel. (+46)(31) 772 3007
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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

NOVEL RESULTS IN HYDROGEN STORAGE AS HYDROGEN
CLATHRATE HYDRATESRita Duarte1, Ali Shariati2, John Zevenbergen3, Louw Florusse1, Cor Peters1
1

Delft University of Technology, Faculty of Applied Sciences, DelftChemTech, Physical
Chemistry and Molecular Thermodynamics, Julianalaan 136, 2628 BL Delft, The Netherlands;
2
Shiraz University, Chemical Engineering Department, Shiraz, Iran; 3TNO Defence, Security
and Safety, Lange Kleiweg 137, 2288 GJ Rijswijk, The Netherlands
It has been discovered that cyclopentane is a significantly better promoter than tetrahydrofuran to stabilize
structure sII of hydrogen clathrate hydate. In addition, promoters were found to stabilize structure sH. This
structure is supposed to have a larger storage capacity for hydrogen. Finally, kinetic aspects of the uptake
and release of hydrogen in structure sII was studied.

Introduction
In our earlier work [1], we discovered that
tetrahydrofuran (THF) is able to stabilize
structure sII of hydrogen clathrate hydrate atmild conditions, with as a result that it wasrecognized as a potential storage material forhydrogen. Additional research did learn that
cyclopentane (CP) is an even better
promoter than THF for structure sII. Also, forthe first time, we were able to find promotersto stabilize structure sH, which structure is
supposed to have a higher storage capacity
for hydrogen. A major issue are various
kinetic aspects that govern the uptake,release and the rapid formation of thematerial in large quantities.

Experimental
To test the applicability of the new promotersfor both structures sII and sH, high-pressurephaseequilibrium
experiments
were
conducted. For the kinetic studies a new
facility was build.

At a temperature of 281 K an equilibriumpressure as low as of 2 MPa turned out to befeasible. Neutron scattering experiments arein progress to determine the hydrogenstorage capacity of this material.
Among others, methylcyclohexane (MCH)
was found to be able to stabilize structuresH, which structure should have a higher
storage capacity for hydrogen. Unfortunately,
the equilibrium pressures at ambient
temperature are in the range of 50 – 70 MPa,
which is too high for a practical material [2].
Finally, we studied the kinetics of hydrogen
uptake and release in structure sII. It was
found that both processes are completely
reversible [3]. A spray technique proved thatthe solid material easily can be produced inlarge amounts.

References
[1]
[2]
[3]

Florusse et al., Science 306 (2004) 469.
Duarte, et al; J. Phys. Chem. B, in press.
Duarte et al. J. Phys. Chem. B, submitted.

Results

Acknowledgement

It was established that CP is a significantly
better promoter than THF to stabilize
structure sII of hydrogen clathrate hydrate.

ACTS / NWO (Praktische Verkenning) andEC FP6 (NESSHY contract no. 518271).

Corresponding author: Cor Peters, email: C.J.Peters@tudelft.nl, Tel. (+31) 15 278 2660

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LOW TEMPERATURE RAMAN SPECTROSCOPY OF LiBH4 AND
LiBD4
J. Schoenes and A.-M. Racu
Technische Universität Braunschweig, Institut für Physik der Kondensierten Materie, D-38106
Braunschweig, Germany

Z. Lodziana, A. Borgschulte, and A. Züttel
EMPA Materials Sciences and Technology, Department of Mobility, Environment, and Energy,
Division Hydrogen and Energy, Überlandstrasse 129, 8600 Dübendorf, Switzerland
With theoretical 18 mass % hydrogen storage capacity LiBH4 belongs to the metal hydrides with thelargest gravimetric and also volumetric hydrogen storage density. Yet, automotive applications also requirefavorable thermodynamic and kinetic properties which are closely related to the bonding of hydrogen in thecompound. Vibrational spectroscopy is particularly suited to study hydrogen bonds, since the light mass ofhydrogen generates high vibrational frequencies and the isotope effect on substitution of deuterium forhydrogen is the largest of any element [1,2]. We report an extensive Raman scattering study of LiBH4 and
LiBD4 for temperatures from 5 to 300 K.

Introduction
A previous study was limited to temperaturesat and above room temperature [3] where
many of the Raman lines are weak or eveninvisible.

Results
The experimental results are compared totheoretical values obtained from a density
functional calculation within the generalized
gradient approximation. The factor group
analysis for the orthorhombic Pnma structure
reveals 36 Raman active modes, of which 18
are external vibrations and the second halfcorrespond to internal (stretching andbending) modes. Up to 24 of these modes
have been observed and assigned to thesymmetry species. An astonishingly good
agreement between experiment and theory isfound for most of the phonon frequencies.
The temperature dependence of thenormalized frequency, linewidth and intensityof the Raman modes shows an anomalous
behavior for one of the external modes with
B3g symmetry. A fit of the linewidth of thismode including an exponential factor
indicates a strong coupling of the mode to
the librational motion of the BH4tetrahedrons. We anticipate that this mode isrelated to the structural phase transition fromthe orthorhombic to the hexagonal phaseoccurring at about 380 K.

References
[1]
[2]
[3]

H. Kierey, M. Rode, A. Jacob, A.
Borgschulte, and J. Schoenes, Phys. Rev. B
63 (2001) 134109
J. Schoenes, A.-M. Racu, M. Rode, and S.
Weber, J. Alloys Compd. 446-447 (2007),
pp. 562
S. Gomes, H. Hagemann, and K. Yvon, J.
Alloys Compd. 346 (2002), pp. 206

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

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

RAMAN SPECTROSCOPY TO PROBE HYDROGEN-DEUTERIUMEXCHANGE REACTIONS IN SODIUM ALANATE.
Andreas Borgschulte, Paul Hug and Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
NaAlH4 is the archetypical complex hydride for hydrogen storage. The enormous effect of dopants on thesorption kinetics triggered the investigation of its physical origin. In this paper, a short review of the state of
the art is given. To gain further understanding of the involved mechanisms we label the interacting species
during the sorption process. This was experimentally realized by hydrogen-deuterium exchange
measurements during the decomposition of NaAlH4 followed by thermogravimetry and Raman
spectroscopy. By these experiments we are able to obtain special information on the diffusing species andformation of intermediates. The activation energy of tracer diffusion in NaH is was found to be 0.25 eV.
The activation energy of tracer diffusion in Ti-doped NaAlH4 is estimated to be approximately 0.2 eV. The
results are evidence for a vacancy mediated desorption process of NaAlH4.

Introduction

Results

Doped sodium alanate is the archetypicalhydrogen storage material for mobile
applications [1]. It decomposes in two steps,
releasing theoretically 5.6 mass% hydrogen[2]. To gain an insight into the involved
mechanisms we label the interacting species
during the sorption process. This isexperimentallyrealizedbyhydrogendeuterium exchange measurements during
the decomposition of NaAlH4 followed bythermogravimetry and Raman spectroscopy.

The diffusion of deuterium in pure solid
NaAlH4 is extremely slow. In liquid phase,exchange of hydrogen as well as diffusion isconsiderable. In Ti-doped NaAlH4, exchangeof hydrogen and diffusion is possible. The
exchange process is coupled to thedecomposition of NaAlH4. In pure solid
NaAlH4, the internal Al-H vibrations are
hardly affected by a temperature increase - incontrast to the external Na – AlH4 vibrations.
Ballmilled, Ti-doped NaAl4 does not show
significant differences of the Raman
spectrum when compared to the purecompound at room temperature. Changes ofthe spectra are observed at 50°C. From thiswe conclude that AlH3 vacancies in NaAlH4
are formed during the decomposition
process, allowing the transport of metal
atoms as well as hydrogen.

Experimental
A magnetic suspension balance Rubotherm(Bochum, Germany) was used to measurethermodesorption kinetics in hydrogen anddeuterium atmosphere, respectively, up to atemperature of 750 K. Raman spectra wereobtained in backscattering geometry using a
Renishaw Ramascope 2000 (Renishaw plc,
Gloucestershire, UK) with a spectral
resolution of 1 cm-1.

References[1][2]

B. Bogdanovic, U. Eberle, M. Felderhoff and
F. Schüth, Scripta Mater. in press (2007).
J. A. Dilts and E. C. Ashby, Inorganic
Chemistry 11, 1230 (1972).

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

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MONITORING THE SNTHESIS OF LiBH4 BY IN-SITU NEURONDIFFRACTION
Arndt Remhof, Oliver Friedrichs, Florian Buchter, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
We demonstrate the direct, solvent free synthesis of Li[B11D4] from the corresponding elements at
T=350°C and p(D2) = 180 bar. The reaction is realized by applying the pressurized deuterium to a preannealed Li-B mixture. The involved intermediate products and the synthesis of the final products weremonitored by in-situ neutron diffraction. The reaction starts with the decomposition of the initial Li-B
compound and the formation of LiD at 200 °C. At 350 °C LiBD4 starts to form. At this temperature thereaction to LiBD4 is not complete, it takes temperatures of more than 500 °C to fully transfer the elements
involved to LiBD4.

To monitor the synthesis of LiBH4 from thecorresponding elements, we used in-situ
neutron diffraction The experiment was
carried out at the focusing diffractometer E6of the Berlin Neutron Scattering Center(BENSC) of the Hahn – Meitner Institute(HMI) in Berlin, Germany. The diffractometeris equipped with a horizontally and verticallybent monochromator consisting of 105
pyrolytic graphite crystals (20 x 20 x 2 mm3)
mounted on a 15 x 7 matrix leading to a fluxof 5 x 106 n/cm2s at the sample position
using neutrons of the wavelength of λ = 0.24
nm.
We first filled a standard stainless steel
sample container with a mixture of ball-milled
11
B and natural Li, corresponding to thestoichiometry LiB3 and placed it into a hightemperature furnace (HTF), After heat
treatment at 330°C for 60h in inert He
atmosphere, the HTF was placed onto thesample stage of the E6 instrument and thesample container was connected to the gas
loading system, supplying deuterium (D2) at
180 bar. LiBD4 melts at 280°C, allmeasurements have been carried out atroom temperature, except the one recorded
at 200°C.

The intermetallic Li-B compound ischaracterized by a strong reflection at2θ=40°. Above 200°C the sample absorbs D2
at large ammounts, and LiD is formed. At
about 350°C LiBD4 can clearly be identified,
together with an increasing amount of LiD.

Fig. 1 Synthesis of LiBD4, monitored by neutron
powder diffraction

Increasing the temperature to 500°C leads toa decrease of the LiD-reflection and to afurther increase of the LiBD4 reflections.
Higher temperatures and/or more time isnecessary to complete the reaction.

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

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ROLE OF Nb2O5 ADDITIVES IN THE HYDROGEN SORPTIONKINETICS OF NANOCRYSTALLINE Mg
Asunción Fernández1, Oliver Friedrichs1,2, Juan Carlos Sánchez-López1, Diego
Martínez-Martínez1, Thomas Klassen3, Rudiger Bormann3
1Instituto de Ciencia de Materiales de Sevilla CSIC-US, Sevilla, Spain. 2Empa Materials Scienceand Technology, Dübendorf, Switzerland. 3Institut für Werkstoffforschung, GKSS Forschungszentrum, Geesthacht, Germany
In the present work we investigate the hydrogen sorption mechanism in a MgH2/Nb2O5 composite andanalyze why Nb2O5 could strongly improve hydrogen sorption kinetics in magnesium. A detailed
microstructural and chemical analysis of the evolution of the additive during the H2 sorption processes
allowed us to identify the formation of ternary Mg-Nb-O phases that during migration to the surface
produce “pathways” allowing the easy diffusion of hydrogen into the Mg nanocrystals.

Introduction
Nano-crystalline MgH2 powders produced byhigh energy ball milling [1] show a significant
progress in the sorption kinetics compared tobulk polycrystalline Mg. The addition of
additives, mainly transition metals andoxides, during ball milling of MgH2 introduced
also a big improvement in the hydrogen
sorption kinetics [2]. Nb2O5 was one of thebest additives found. Here we present our
results to elucidate the mechanism by whichthese oxides are improving the kinetics.

Experimental
The samples were ball milled-MgH2,
additionally milled with 5-10 wt% Nb2O5 asadditive. Samples characterization was
carried out by XRD, XPS, TEM and XAS.
Kinetic sorption measurements were carriedout by a volumetric Sievert apparatus.

Results
Here we present our results indicating theformation of ternary Mg-Nb-O phases [3] thatduring migration to the surface produce“pathways” allowing the easy diffusion ofhydrogen into the Mg nanocrystals. Hereby
we also show the application of Nb2O5-

nanoparticles as milling additives [4], bywhich the milling time could be reduced bymore than a factor 200 compared to asystem of MgH2 milled with microcrystalline
Nb2O5.

Fig.1. Formation of hydrogen pathways throughthe MgH2 and the MgO surface oxide layer. Left:original sample. Right: Sample after firstdesorption.

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

Zaluska et al; J. Alloys Compd. 288 (1999)
217
Oelerich et al; J. Alloys Compd. 315 (2001)
237
Friedrichs et al; Acta Mat. 54 (2006) 105;
J.Phys.Chem.C 111 (2007) 10700
Friedrichs et al; Scripta Mat. 54 (2006) 1293;
J.Phys.Chem.B 110 (2006) 7845

Corresponding author: Asunción Fernández, e-mail: asuncion@icmse.csic.es, Tel. (+34) (95) 448 9531

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FLOW-PCT METHOD FOR CHARACTERIZATION OF HYDROGEN
STORAGE MATERIALS
Michael Bielmann, Shunsuke Kato, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec. Hydrogen& Energy, CH-8600 Dübendorf, Switzerland
In this contribution, the thermodynamic characterization by the so called Flow-pcT is presented for thebenchmark material of LaNi5. This method, in contrast to the Sieverts-PCT, is continuous and therefore
eliminates this inherent draw back of volumetric characterization methods. The measurement process aswell as the data analysis to obtain the Van’t Hoff plot and hence the thermodynamic parameters of thestorage material is explained by measurements on LaNi5 as a benchmark due to the well characterized
properties of this material. The results match perfectly the literature values for this material of ∆H = -32.5
kJ/molH2, ∆S = -115 kJ/molH2 and and show the validity and quality of the Flow-pcT method.

Introduction
The determination of ∆H and ∆S from Van’t
Hoff Plots are the usual way forthermodynamical
characterizationofhydrogen storage materials. There exist a
multitude of methods for the construction of
van’t Hoff Plots whereas the volumetric
Sieverts method is the most frequently
applied. This method, consisting of a knownreference volume filled with hydrogen whichis expanded into the sample cylinder andestablishing the amount of hydrogen sorbed
from the ideal gas laws - while conceptuallyapparently simple, suffers from a multitude ofcomplications due to the inherent step-bystep approach of data acquisition which
render data analysis complicated and difficult[1]. Data acquisition in a manual system istedious as each measurement point needs tobe recorded individually, involving valve
actuation. The flow-pcT method eliminates
many draw backs and while conceptuallymore complicated offers many advantages
which are presented in this presentation.

Experimental
The flow-pcT method is based on theconcept of exposing the sample to be
characterized to a constant flow of hydrogen
while
recordingthepressureandtemperature over the sample. While this typeof measurement is not in equilibrium bydefinition, variation of the flow for different
measurements an extrapolation of theplateau pressure towards zero-flow e.g.
equilibrium pressure is a straight forward
process. From the equilibrium pressures atgiven temperatures, the evaluation of the
van’t Hoff plot directly reveals the sought
thermodynamic parameters. The schematicconcept, the acquisition process and analysisof the data are presented using wellcharacterized LaNi5 as a benchmark
material. The acquisition process is
continuous, eliminating user-action for theacquisition of one run and increasing point
density by orders of magnitudes hence
improving vastly the quality of acquired data.

Results
The
processofestablishingthethermodynamic parameters is discussed
from the raw data measurements to the final
results for LaNi5 at different temperaturesand flows for desorption experiments. The
excellent agreement with tabulated values
underlines the quality of this type ofmeasurements.

References[1]

T.P. Blach, E. MacA. Gray, J. Alloys Comp.,
446-447 (2007) 692-697

Corresponding author: Michael Bielmann, email : michael.bielmann@empa.ch Tel.:(+41) (44) 823 43 42

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2nd Hydrogen & Energy Symposium

CALCULATIONS
CLUSTERSON

Braunwald, Switzerland 2008

HYDROGENIN

NANOSCALE

METAL

Hannes Jonsson
University of Iceland, Science Institute, Chemistry Division, Dunhaga 3, 107 Reykjavik, Iceland
The results of theoretical, DFT calculations on hydrogen in small metal clusters containing mainly
aluminum and/or magnesium and, in some cases, also some transition metal will be presented. The
results indicate that small MgH2 clusters release hydrogen at a higher temperature than the crystal, unlessthe clusters are extremely small, with fewer than 5 atoms. The addition of Ni or Zr does not significantly
affect the desorption temperature. The results on the Al and Al-H clusters are quite unexpected andpromising. As hydrogen is adsorbed, the cluster deforms and opens up so as to accommodate nearly
three hydrogen atoms per Al atom, giving about 10% hydrogen by weight. Since the hydrogen atoms bindat surface sites, the binding energy is much stronger than in bulk AlH3, about 0.20 eV per hydrogen atom,
close to the target value for hydrogen storage.

Corresponding author: Hannes Jonsson, email: hj@hi.is; Tel. (+354) 525 4643

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DFT MODELLING OF NOVEL MATERIALS FOR HYDROGEN
STORAGE
Tejs Vegge,1 Johannes Voss,1,2 Jens Strabo Hummelshøj,1,2 Jens K. Nørskov2
1)

Materials Research Department, Risø DTU and 2) Center for Atomic-scale Materials Design
and Department of Physics, Technical University of Denmark
Quantum chemical computer simulations based on density functional theory (DFT) have shown great
potential in the search for novel materials for reversible solid state hydrogen storage. This is particularly
true for the high capacity alanate and borohydride systems, which are both difficult to synthesize andcharacterize experimentally, and require the use of catalysts for practical applications. As of now, many of
the fundamental properties, rate limiting processes and catalytic interactions in these materials remains to
be understood.

Introduction
We present a number of examples illustrating
the potential of DFT calculations in the
search for better materials for hydrogenstorage. The examples range from alloy
screening studies using simple model
structures to the characterization andprediction of stability at finite temperatures ofnovel structures and materials.

of NaAlH4, including hydrogen desorption
and diffusion processes is investigated [2],and DFT is used to analyze thermodynamic
properties, characterize structures and phasetransitions in LiBH4 [3] and Mg(BH4)2 [4].

Calculations
Electronic
structure
calculations
areperformed using density functional theory in
the DACAPO plane wave basis set [1] andVASP implementations. Lattice dynamics
and vibrational free energies are calculated,using the PHONON code, to investigate
stability at finite temperatures, andcalculations of diffusion rates are based on
the NEB method and transition state theory.

Results
Close integration of the DFT calculations withexperimental techniques, such as quasielastic neutron scattering (QENS) and smallangle X-ray scattering (SAXS), is used toprovide new insight into the catalytic andnano-scale properties of the materials forhydrogen storage. The role of titanium based
catalysts on the reversible de-hydrogenation

Fig. 1. The proposed 704 atoms Fddd structure ofβ-Mg(BH4)2 [3].

Results on indirect storage of hydrogen in theform of ammonia stored in metal ammines,
e.g. Mg(NH3)6Cl2 and Ca(NH3)8Cl2 will also
be presented [5].

References
[1]
[2]
[3]
[4]
[5]

Dacapo pseudopotential code. URL
http://www.fysik.dtu.dk/campos
Voss et al., J Phys Chem B 111, 3886 (2007)
Her et al., Acta Cryst. B63, 561 (2007)
Lodziana and Vegge, PRL 97, 119602 (2006)
Hummelshøj et al. JACS 128, 16 (2006)

Corresponding author: Tejs Vegge, email: tejs.vegge@risoe.dk, Tel. (+45) 4677 5818

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ABOUT THE STABILITY OF COMPLEX HYDRIDES
Andreas Züttel, Andreas Borgschulte, Oliver Friedrichs, Tomoya Matsunaga
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The stability of a metal hydride is defined as the difference between the enthalpy of the hydride and theenthalpy of the metal or intermetallic compound. This difference is considered to be the same for thehydrogen absorption and desorption reaction, neglecting inelastic effects causing a hysteresis. For
complex hydrides the enthalpy of formation is given by the enthalpy of the complex hydride, while thehydrogen desorption takes place via intermediate products leading to an enthalpy for desorption which issignificantly smaller than the enthalpy of formation.

Introduction
The stability of complex hydrides is investigated 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 neutral and “hypothetical”
TH3 is also determining the equilibriumpressure of the complex hydride.

Theory and Model
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]. The stability of the AlH3
< BH3 < NH3, therefore, alanates decompose
into hydrogen and aluminum while boranates
tend to liberate beside hydrogen also B2H6
andtheammonium
spontaneously
decomposes into NH3. Therefore, thethermodynamics i.e. stability and kinetics is
calculated based on the intermediate
products identified.

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

The appearance or the induced creation ofintermediate products in the hydrogen
desorption reaction is a possibility to destabilise the complex hydrides and to
facilitate the reversible hydrogen absorption[3].

References[1]

Results
The stability of the TH4- is determined by the
localization of the electron on the T-atom [2].
As a consequence the stability of thecomplex hydride strongly depends on theelectronegativity of the cation. However, thisapproach is only able to describe the stabilityof the forth hydrogen atom in the anion.

[2]

[3]

Andreas Züttel, Andreas Borgschulte andShin-Ichi Orimo, « Tetrahydroborates as newhydrogen storage materials », Scripta
Materialia, Volume 56, Issue 10, May 2007,
pp. 823-828
Shin-Ichi Orimo, Yuko Nakamori, Jennifer R.
Eliseo, Andreas Züttel and Greg Jensen,« Complex Hydrides for Hydrogen Storage »,Chemical Reviews, October 2007, Volume
107, Number 10, pp. 4111-4132
Goerrig, D; Deutsches Patent; Auslegungsschrift (1960) DE000001077644A

Corresponding author: Andreas Züttel, email: andreas.zuettel@empa.ch, Tel. (+41) (44) 823 4038
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SOME APPLICATIONS OF INS AND DFT IN HYDROGENCONTAINING MATERIALS, THERMODYNAMICS STUDY OF THE
STRUCTURAL AND DYNAMICAL PROPERTIES
Anibal J. Ramirez-Cuesta
ISIS facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, United Kingdom
The neutron is an ideal probe for the study ofhydrogenous materials [1]. Neutrons arescattered by atomic nuclei. All molecularvibrations are neutron-active because thenuclear interactions are not subject to dipole
or polarisability selection rules. All vibrations
are in principle, observable. Because theneutron has a mass, it also allows the
sampling of the vibrations in the Brillouinzone. The intensity of the vibrational modes
is proportional to the amplitude of motion of
the atoms in the solid; this combined with thelack of selection rules makes the comparisonof calculated spectra with experimental
straightforward [2]. All these characteristics
combined make INSS (Inelastic Neutron
Scattering Spectroscopy) an ideal test bed
for the applicability of quantum mechanicalab initio calculations.
In the solid it is possible to take into
consideration quantum effects by means ofthequasi-harmonic
latticedynamics
approximation. The quantity to be minimisedis the Helmoltz free energy, which includes
the zero point motion as well as thermal
effects. This approximation is considered to
be valid over a wide range of temperatures,but it is especially valid up to room
temperature [3].
We tested different functional in DFT
calculations and found that in the case of thewhole series of simple metal hydrides (LiH …
CsH) the better structural and dynamical
agreement, for calculations including thermal
effects was when using LDA functionals
rather that the most widely “trusted” GGA
functionals. Further studies demonstrated
that the same effect is observed on othersystems, most notably in polyethylene [4].
In this talk I’ll address the capabilities of INS
spectroscopy and the correspondence withabinitio dynamical calculations.

References[1] Vibrational Spectroscopy with Neutrons; PCH
Mitchell, SF Parker, AJ Ramirez-Cuesta and
J Tomkinson, World Scientific, London 2005.
[2] Ramirez-Cuesta, A. J. Computer Physics
Communications 2004, 157 (3), 226-238.
[3] Barrera, G. D.; Colognesi, D.; Mitchell, P. C.
H.; Ramirez-Cuesta, A. J. Chemical Physics
2005, 317 (2-3), 119-129.
[4] Barrera, G D.; Parker SF; Ramirez-Cuesta AJ;
Mitchell P. C. H. Macromolecules 2006, 39,
2683-2690

Corresponding author: Anibal J. Ramirez-Cuesta, email: a.j.ramirez-cuesta@rl.ac.uk, Tel. (+44)
1235 44 6510
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MAY TITANIUM BE A GOOD CATALYST FOR LiBH4 SYNTHESIS?
Zbigniew Łodziana, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
Titanium is known additive that can catalyze synthesis and decomposition of sodium alanate (NaAlH4). For
lithium borohydride (LiBH4) such additive is not known. While Ti affects decomposition of lithium
borohydride it has no effect on synthesis of this compound. We have analyzed interaction of Ti with bothcompounds. Incorporation of Ti into the bulk of NaAlH4 may be exothermic for high oxidation states of Ti
cation, unlike for LiBH4.

Introduction
The catalytic effect of metal additives on
kinetics of hydrogen adsorption/desorption is
not understood on the microscopic level,
even for sodium alanate. In particular, it isstill under debate whether Ti affects only thesurface or it also influences stability of thebulk NaAlH4. Several theoretical studies
provide insight into interaction of Ti atoms
with NaAlH4. No method that facilitates LiBH4
as a practical hydrogen storage media is
known.

oxidation states of Ti are unstable one thesurface of sodium alanate and lithium
borohydride but under certain conditions Tin+
cations are stable in the bulk of NaAlH4. Tin+
cations incorporated into alanate locallymodify charges on the AlH4 groups. For Ti
inside NaAlH4 bonding states to the closest
Al are observed, while in LiBH4 Ti orbitals are
localized exclusively on Ti, see Fig. 1.

MethodPeriodic density functional (DFT) method andthermodynamic considerations were used to
study formation energies of Ti related defects
in complex hydrides and the electronic
structure modifications related to formation of
Ti defects (substitutions and interstitials) inthe bulk and on the surface.

Results
We have shown that description of Ti
incorporation process in/on NaAlH4 and
LiBH4 shall include not only neutral atoms,
but account for the charge transfer effects
that was omitted in the literature. Higher

Fig. 1. Local density of states (dashed line)
projected on B in LiBH4 (a) and Al in NaAlH4 (b)ions that are closest to interstitial Ti. The LDOS for
undoped samples are shown by thick solid linesand LDOS projected on Ti are shown by thin solidlines for the reference. The insert shows the real
space projection of neutral Ti gap states. Smaller(blue) sphere is for Ti, larger (gray) for Al.

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

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2nd Hydrogen & Energy Symposium

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ALKALINE METAL-BORON SYSTEMS: FIRST PRINCIPLESCALCULATIONS.
Riccarda Caputo, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
First-principles calculations of the electronic structure of MxBy (M = Li, Na, K) has been performed toinvestigate the stability of interstitial metal atoms dissolved in rhombohedral phase of boron. Lattice
distortions and bulk properties are analysed comparing the action induced by different alkaline metals.
Surface processes at low coverage are also investigated to elucidate the mechanism of reaction metalboron. The present study represents the first step towards a comprehensive description of ternary phase
diagram metal/boron/hydrogen.

Introduction
The importance of alkaline metal/boron
systems has recently rewind due to theenormous interest in light metal borohydrides
as suitable compounds for hydrogen storage.
In order to describe and hence drive themechanism of the solid state reaction
between a metal and boron, it is quite crucial
to clarify the chemical nature of theinteractions involved at atomistic level.

Computational method

The energy-volume curve calculated at
different compositions can help to elucidate
the chemical action of metal atoms on boron
structure. The lattice distortion and thereticular expansion induced by interstitial
metal atoms indeed clarify the chemical
nature of the bond formed into the bulk.
Surfaceprocessesattheinterfacemetal/boron represent preliminary steps toalloy and compound formation. Thus thepotential energy surface (PES) is calculated
at low coverage.

Wave-function based approach is employedbased on cluster model of metal-boron
systems at CAS-SCF and MP2 level oftheory.
Periodic cell calculations are run at density
functional theory (DFT) level using thegeneralised gradient approximation (GGA)with the PBE functional and a free-energyfunctional at a finite electron temperature, as
implemented in CPMD code.

Results
The structure of α-rhombohedral boron
phase is first optimized at DFT level tocalculate the lattice constant and the bulk
properties, as bulk modulus and electron
density of states. The addition of metal atoms
to the optimized boron lattice enable to study
the bulk interactions of an alkaline metal
dissolved as interstitial into the host lattice.

Fig. 1. α-rhombohedral boron phase (left), LiB3
structure (right) obtained from DFT calculations
via geometry optimization of α-boron
rhombohedral lattice with interstitial lithium.

References[1]

H.B. Borgstedt, J. Phase Equilibria 24(2003),572

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

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OXYGEN EVOLUSION REACTION IN DIFFERENT CONTEXTSJan Rossmeisl, Heine A. Hansen, Kristian Dimitrievski, Per Siegbahn, Jens K.
Nørskov
Center for Atomic-scale Materials Design, Department of Physics, Nano-DTU, Technical
University of Denmark, 2800 Kgs. Lyngby, Denmark
We perform density functional theory (DFT) calculations to analyze the electrochemical water-splitting
process producing molecular oxygen (O2) and hydrogen (H2). We investigate the trends in the electrocatalytic properties of (110) surfaces of rutile-type oxides (RuO2, IrO2, PtO2, MnO2 and TiO2). The oxide
anodes show lower O2-evolving over-potentials than metal anodes, due to weak O binding but stronghydroxyl (HO*) binding on the surface. The binding energies of O, HO, and HOO on the (110) surfaces
fulfill universal linear relations similar to those found on metal surfaces. Furthermore we compare theoxides to the Mn-cluster from photo system II. We find that the thermo-chemical features of the catalysts
can be directly compared. We identify the optimal binding of the oxidations states and find that the Mncluster in photosystem II is close to optimal, even better than the best inorganic surfaces RuO2 and MnO2.

Introduction
Electrolysis of water is a route to produce
pure CO-free hydrogen and dependent on
the energy source possibly non-polluting.
However, the reaction is in general relatedwith a substantial overpotential and an
effective catalyst for this reaction is therefore
needed. We investigate the origin of theover-potential for elemental metal oxidesurfaces applying density functional theory
calculations [1]. In biology oxygen evolution
is one of the steps in photosynthesis where
evolution oxygen is a byproduct and anecessary condition for all higher life forms.
We compare the biological enzyme to the
inorganic catalysts [2]. The best known
anode catalysts are RuO2 known to show thelowest overpotential. In nature the same
reaction is catalyzed by a Mn-cluster that has
been conserved throughout history of
evolution.

associative mechanism on the anode via asurface HOO* intermediate. We find that the
overpotential of the rutile oxides can be
described by the oxygen binding at thesurface see, Fig 1

MethodReferences

We consider the reaction:
+

-

+

-

[1]

The * represents an active surface site. We
are only considering reaction steps involving
charge transfer, which depend directly on theapplied potential. We consider a process
where oxygen molecules are formed by an[2]

2H2O → HO* + H2O + H + e → O* + H2O + 2H + 2e++

→ HOO* + 3H + 3e-→ O2 + 4H + 4e-

J. Rossmeisl, Z.-W. Qu, H. Zhu, G.-J. Kroes
and J.K. Nørskov, J. Electroanalytical Chem.
607 (2007), pp. 83-89
J. Rossmeisl, K. Dimitrievski, P. Siegbahn,
J.K. Nørskov. In press. Letter in Phys.
Chem. C. (2007)

Corresponding author: Jan Rossmeisl, email: jross@fysik.dtu, Tel. (+45) (45) 253 166
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LITHIUM AND SODIUM AMIDOBORANES – NEW HIGH CAPACITYHYDROGEN STORAGE MATERIALSPeter P Edwards1, Martin Owen Jones1, Simon R Johnson1 and William I FDavid2, Zhitao Xiong3, Chaw Keong Yong3, Guotao Wu3 and Ping Chen3,4
Wendy Shaw5, Abhi Karkamkar5 and Thomas Autrey5
1

Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxon, OX11 0QX, UK
3
Department of Physics, 4Department of Chemistry, Nat. Uni. of Singapore, Singapore 117542
5
Pacific Northwest National Laboratory, Richland, WA 99352, United States
2

The safe and efficient storage of hydrogen is widely recognized as one of the key technological challenges
in the transition towards a hydrogen-based energy economy1-2. Ammonia borane, NH3BH3, is one of anumber of condensed phase compounds that have received significant attention because of its reported
release of ~12wt% hydrogen at moderate temperatures (~150°C). However, the hydrogen purity suffersfrom the release of trace quantities of borazine. In this letter, we report that the related alkali metal
amidoboranes, LiNH2BH3 and NaNH2BH3, release ~10.9wt% and ~7.5wt% hydrogen, respectively, atsignificantly lower temperatures (~90°C) with no borazine emission.

Introduction
We report the synthesis and structure oflithium amidoborane (LiNH2BH3) and sodium
amidoborane (NaNH2BH3) and report thatthey show substantially different andimproved dehydrogenation characteristics
with respect to ammonia borane itself.

compound, ammonia borane. Alkali metal
amidoboranes are also environmentallyharmless, non-flammable, non-explosive andstable solids at room temperatures andpressures.

Experimental
LiH, NaH and NH3BH3 (95%, 95% and above
90%, respectively), were used without further
purification in hydride/AB molar ratio of 1:1
and were ball-milled on a Retsch PM400
planetary mill at 200rpm. Graphite wasadded to the mixture to enhance ball milling
efficiency.

Results
Alkali metal amidoboranes, LiNH2BH3 andNaNH2BH3, satisfy a number of the principal
criteria demanded for hydrogen storage
media. LiNH2BH3 and NaNH2BH3 provide
high gravimetric weight percents (10.9wt%
and 7.5wt%, respectively) of hydrogen at
easilyaccessible
dehydrogenation
temperatures (ca. 90°C) without unwanted
by-products, borazine. These materials offer
significant advantages over their parent

Fig. 1.
The
NaNH2BH3.

Structureof

LiNH2BH3

andReferences[1][2]

Schlapbach, L. & Zuttel, A. Hydrogenstorage materials for mobile applications.
Nature 414, (2001), pp. 353-358.
Grochala, W. & Edwards, P. P. Thermal
decomposition of the non-interstitial hydrides
for the storage and production of hydrogen.
Chem Rev. 104, (2003), pp. 1283-1315.

Corresponding author: Peter Edwards, email: peter.edwards@chem.ox.ac.uk, Tel. (+44) (18625) 27 2646

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2nd Hydrogen & Energy Symposium

HYDROGENOGRAPHY:HYDRIDES

Braunwald, Switzerland 2008

FROM

Pd

TO

COMPLEXMETAL

B. Dam, R. Gremaud, Y. Pivak, E. Batyrev, J. Rector, H. Schreuders and R.
GriessenCondensed Matter Physics, Department of Physics and Astronomy, Faculty of Science, Vrije
Universiteit, De Boelelaan 1081, NL-1081 HV Amsterdam, The Netherlands
We have demonstrated that the change in optical properties on hydrogenation make metal hydrides
perfectly suited for a thin film combinatorial search for new hydrogen storage materials [1]. Using
Hydrogenography, we measure simultaneously the enthalpy of hydride formation of thousands of materials
on a single thin film wafer. From extrapolation of the optically measured Van ‘t Hoff plots, we obtain theentropy of formation. Using very thin layers of Pd we reproduce the Van ‘t Hoff relation both in absorption
and desorption, the latter data in full accordance with previous literature bulk data [2]. Comparing thesedata with Mg-Ti-H films (which is a mix of coherently ordered fcc MgH2 and TiH2) we find an anomalously
large hysteresis. The steps towards the formation of thin film alanates is a formidable challenge. For thispurpose we set up a dedicated thin film sputtering and analysis system. We will discuss our first attempts
to form alanate thin films by hydrogenation of co-deposited NaH, Al, Ti thin films.

References[1]

Gremaud, R., Ch.P. Broedersz, D.M. Borsa,
A. Borgschulte, P. Mauron, H. Schreuders,
J.H. Rector, B. Dam and R. Griessen,
Hydrogenography: an optical combinatorial
method to find new light-weight hydrogenstorage materials, Advanced Materials 19(2007) 2813-2817[2]

Gremaud, R., M. Slaman, H. Schreuders, B.
Dam, and R. Griessen, An optical method todetermine the thermodynamics of hydrogen
absorption and desorption in metals, Appl.
Phys. Lett 91 (2007) 231916

Corresponding author: Bernard Dam, email: dam@nat.vu.nl, Tel. (+31) (20) 598 7917

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HYDRIDE FORMATION IN MECHANICALLY ACTIVATED MgBASED SYSTEMS
Stefano Deledda1), Ana Borissova1), Marit D. Riktor1), Helmer Fjellvåg2), Bjørn
C. Hauback1)
1)
2)

Institute for Energy Technology, Physics Department, N-2007 Kjeller, Norway
University of Oslo, Chemistry Department, N-0318 Oslo, Norway

We present results for Mg-based powder mixtures which were ball milled (i) at room temperature in an
inert Ar atmosphere, (ii) at liquid nitrogen temperature (cryomilling), and (iii) at room temperature in areactive H2 atmosphere (reactive milling). The structural and microstructural evolution of the powders wasfollowed by powder diffraction analysis. Results on the formation of Mg-based hydrides upon reactive
milling or during conventional hydrogenation of ball milled or cryomilled powders in a Sievert-typeapparatus, are presented. The effect of the different processing conditions, e.g. milling temperature andmilling atmosphere, on the phase-selection process is discussed.

Introduction
Ball milling techniques are consideredbeneficial for processing potential hydrogenstorage materials. This is due to the grainsize reduction process, which occurs during
the continuous fracturing and cold welding of
the powder particles and which results in an
improved H-sorption kinetics [1]. On the other
hand, upon ball milling, elements and/or
compounds are mixed at an atomic scale andthe resulting extended solid solubility
between metals, allows the production ofmetastable alloys, which might showinteresting hydrogen storage properties [2].

Experimental
Powder mixtures with composition Mg67Co33,
Mg67Fe33, or (Mg0.8Ti0.2)67Ni33 were ball milledin Ar using either a Fritsch P6 planetary ballmill or a SPEX 6750 Freezer/Mill. The latterallows milling to be carried out at liquid
nitrogen temperature (cryomilling). For theplanetary mill, a modified vial equipped with avalve allowed milling also in a H2 atmosphereat 5.5 bar. The powders ball milled in Ar were

subsequently hydrogenated in a Sievert-typeapparatus.

Results
Formation of Mg2CoH5 and Mg2FeH6 isachieved by reactive milling in H2 or byhydrogenating,atarelatively
lowtemperature and pressure, the powders ballmilled in Ar. In both cases, the compounds
form directly from the elements, with noindication of formation of MgH2 as aprecursor. Cryomilling has been foundeffective for reducing the particle size and, inturn, for enhancing the kinetics of phaseformation. In addition, cryomilling of Mg-Ti-Ni
powders results in the formation of acomposite consisting of Mg2Ni and a Ticontaining amorphous phase. For such acomposite, absorption in 12 bar H2 occurs at
relatively low temperatures: 2.5 wt.% and 1.9
wt.% H2 are absorbed at 100 °C and 150 °C,
respectively.

References[1][2]

Zaluska, et al; J. Alloys Comp. 288 (1999)
217.
Zhang, et al; J. Alloys Comp. 393 (2005) 147

Corresponding author: Stefano Deledda, email: stefano.deledda@ife.no, Tel. (+47) 63 80 6087

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THERMAL DECOMPOSITION STEPS OF Mg(BH4)2 UNDER HEFLOW AND H2 PRESSURE
N. Hanada, Ch. Frommen, W. Lohstroh and M. Fichtner
Institut für Nanotechnologie, Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe,
Germany
The thermal decomposition steps of Mg(BH4)2, which has 14.9 mass% hydrogen capacity, were
investigated under He flow and various hydrogen pressures up to 50 bar. In a He flow, the main
decomposition of Mg(BH4)2 occurs between 250 and 410 °C until 12.1 mass% is lost, with three main
peaks of hydrogen desorption. In the first decomposition step the crystalline phase of Mg(BH4)2 disappears
while a small amount of Mg is detected in the XRD profile. However, the major part of the sample is in an
amorphous state. After the second step, crystalline MgH2 is observed together with Mg phase. The third
step of hydrogen desorption corresponds to the decomposition of MgH2 and Mg is the only crystalline
phase observed by XRD measurement after heating to 410 °C. Moreover, even after the decomposition of
MgH2, further hydrogen evolution of 1.4 mass% is observed from 410 °C to 550 °C. Only after thishydrogen desorption, MgB2 appears in the XRD spectra of the sample. These results indicate that
amorphous, hydrogen containing boron compounds take part as intermediates in the reaction. Combined
TG - DTA - MS data suggest that the decomposition scheme shows five distinct transformation steps and it
appears to be more complex than the simple scheme suggested in earlier publications [1]. Decomposition
under static hydrogen pressure up to 50 bar, shifts the decomposition steps to higher temperature,
however the decomposition scheme seems to be essentially the same and final stable compound (at500°C) of Mg(BH4)2 is MgB2 in both inert and hydrogen gas atmosphere.

References[1] K. Chlopek, C. Frommen, A. Léon, O. Zabara
and M. Fichtner, J. Mater. Chem., 2007, 17,
3496

Corresponding author: Nobuko Hanada, email: nobuko.hanada@int.fzk.de, Tel. (+49) (7247) 82 6377

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STABILITY AND REVERSIBILITY OF LiBH4
Ph. Mauron, F. Buchter, O. Friedrichs, A. Remhof, M. Bielmann, C.N. Zwicky, A.
ZüttelEmpa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The stability of LiBH4 was investigated by pcT- (pressure, concentration, Temperature) measurements
under constant hydrogen flows and extrapolated to equilibrium. According to the van ‘t Hoff equation thefollowing thermodynamic parameters are determined for the desorption: enthalpy of reaction ∆rH = 74 kJ-1-1
mol H2 and entropy of reaction ∆rS = 115 J K mol-1 H2. LiBH4 decomposes to LiH + B + 3/2 H2 and cantheoretically release 13.9 wt% of hydrogen for this reaction. It is shown that the reaction can be reversed
at a temperature of 600 °C and at a pressure of 155 bar. The formation of LiBH4 was confirmed by XRD(X-Ray Diffraction).

Introduction
In this work the enthalpy ∆rH and entropy ∆rSof reaction of the desorption of LiBH4 were
determined by pcT-measurements. The
logarithm of the equilibrium pressure peq
divided by standard pressure p0 = 1.01325
bar as a function of the inverse temperatureis represented in a van ‘t Hoff plot and ∆rH
and ∆rS are determined according to the van‘t Hoff equation:

in Fig. 1. Because the plateau pressuresdepend on the applied flow ln(pdes/p0) as afunction of the flow is extrapolated to theequilibrium (0 sccm) (red squares). From thevan ‘t Hoff equation the following values were
found: enthalpy of reaction ∆rH = 74 kJ mol-1
H2 and entropy of reaction ∆rS = 115 J K-1
mol-1 H2.
In the rehydrided material 8.3 wt% ofhydrogen was desorbed compared to 10.9
wt% desorbed in the first dehydrogenation.

p  ∆ H 1 ∆ S
ln eq  = r ⋅ − r
R TR p0 

The slope of the straight line is proportionalto ∆rH the axis intercept is proportional to∆rS.

Experimental
For the pcT measurements 250 mg of LiBH4
from Sigma-Aldrich were heated totemperatures between 400°C and 520°C
under a pressure of 20 bar hydrogen. The
measurements were performed at different
constant hydrogen flows of 0.1, 1 and 2 sccm
respectively. The rehydrogenation was madeat a pressure of approximately 155 bar H2 ata temperature of 600 °C for 200 min.

Results
The different plateau pressures for thedifferent temperatures and flows are shown

Fig. 1. Van ‘t Hoff plot of LiBH4 (desorption) [1]References[1]

Ph. Mauron, F. Buchter, O. Friedrichs, A.
Remhof, M. Bielmann, C.N. Zwicky, A.
Züttel, Stability and Reversibility of LiBH4,
The Journal of Physical Chemistry B,
Accepted

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

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CRYSTAL STRUCTURE OF Ca[BD4]2
F. Buchter1, Z. Łodziana1, A. Remhof1, A. Borgschulte1, Ph. Mauron1, A. Züttel1,
D. Sheptyakov2
1

Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland.
2
Laboratory for Neutron Scattering, ETH Zurich & Paul Scherrer Institute, CH-5232 Villigen PSI,
Switzerland.
Ca[BH4]2 with a high gravimetric hydrogen density of 11.5 mass% is among the most promising hydrides
for hydrogen storage. The crystal structure of Ca[BH4]2 was to a large extent still unknown, with a variety ofstructures found depending on the synthesis process and temperature of the samples.

Introduction

Results

A room temperature crystal structure of
Ca[BH4]2 obtained by drying Ca[BH4]2·2THF
was recently determined and called α-phase[1]. In sample synthesized from MgB2 bysolid gas mechanochemical reaction [2], theroom temperature α-phase of Ca[BH4]2
phase was found to transform to a unsolved
β-phase of Ca[BH4]2 at about 130°C [2]. In
sample synthesized by wet chemical method[3], coexistence of a unsolved γ-phase withthe β-phase from room temperature up to
330ºC [4].

For the determination of the structure of the
β-phase, investigation of eight space group
candidates, combined with a detailed abinitio calculation of the formation andvibrational energy, have shown the structuralmodel with space group P42/m (# 84) to be
the best candidate combining the lowest
energy and highest symmetry [5]. For the γphase,astructural
candidatewithorthorombic space group Pbca (# 61) has
been found [5]. Ab-initio calculation has
shown these models to be stable with similarenergy compared to the the α-phase,
explaining the coexistence of α-phase, γphase and β-phase in the range 20ºC to
290ºC.

Experimental
We have investigated and solved the crystal
structure of the β-phase and γ-phase of
Ca[BD4]2 by combined X-ray and neutron
diffraction on a sample synthesized from
MgB2 by mechanochemical reaction and on asample synthesized by wet chemical method[5]. Experimental results were supported byab-initio calculations in order to find the
optimal structural candidates.

References
[1]
[2]
[3]
[4]
[5]

K. Miwa, et al., Phys. Rev. B 74, 155122(2006).
G. Barkhordarian et al., accepted in Journalof Physical Chemistry.
K. Chlopek, et al., 17, 3496-3503 (2007).
M. D. Riktor et al. J. Mater. Chem.,
2007,DOI:10.1039/b712750b
F. Buchter et al. Submitted

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

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HYDROGEN IN THE ATMOSPHERE
Martin Steinbacher, Martin K. Vollmer, Steven W. Bond, Brigitte Buchmann,
Stefan Reimann
Empa Materials Science and Technology, Laboratory for Air Pollution / Environmental
Technology, CH-8600 Dübendorf, Switzerland
Molecular hydrogen (H2) is one of the most abundant trace gases in the atmosphere. It has recently
become of wider atmospheric interest for various reasons among which is the ongoing discussion on
switching our fossil-fuel based economy to a hydrogen-based economy. Such a potential change may
result in drastic changes of the atmospheric H2 budget. To better predict the impacts of enhanced
anthropogenic H2 usage to the atmospheric H2 budget, better constraints on the currently poorly known
budget are a prerequisite. For this reason attempts are being made to understand and quantify actual
sources and sinks of H2 to the atmosphere.

Gubrist Tunnel: St. Gal Bore, H2 Accumulation in Tunnel
1
10
0.8

We investigate H2-related processes in theatmosphere
by
means
of
chassisdynamometermeasurements,
highwaytunnel studies [1] as well as air quality
monitoring at a suburban sampling site near
Zurich [2] and at a high altitude researchstation (Jungfraujoch; 3580 m asl). The
integration of all these measurements allows
assessing the source of the automobile
exhaust of H2, evaluating the trend ofanthropogenic H2 emissions, assessing theH2 uptake by soils as well as a determinationof the current background atmospheric H2
loading, trend analysis and an investigationof long-range transport of H2.

6
0.4

4

0.2
0

Mo
11/29

2

Results

0.6

H [ ppm ]83

H2 is often regarded as a key component in
the future energy chain. Consequently,
several governments intensified their supportof the development of hydrogen technology
and infrastructure. Before the hydrogen
economy becomes reality, the impact of thedifferent emissions on the atmosphereshould be investigated in detail and thecurrent budget has to be entirely understood.
Wesummarize
thestate-of-the-art
knowledge of the H2 budget and the current
understanding of H2-related processes in theatmosphere.

Fig. 1 exemplarily shows the time series ofH2 accumulation (tunnel exit minus tunnel
entrance) in a highway tunnel. It exhibits astrongdiurnalcycle
withhighestconcentrations during the morning andevening rush hours. This illustrates thedominant role of traffic emissions on the H2levels in the tunnel. On weekends, morningand evening peaks are less pronounced.

H2 [ mg m ]Introduction

2

Tu
We
12/01

Th
Fr
12/03
Date in 2004

Sa
Su
12/05

0
Mo
12/07

Fig. 1. Time series of H2 accumulation in a
highway tunnel.

References[1][2]

Vollmer et al; Atm. Env. 41 (2007) 8355
Steinbacher et al; Atm. Env. 41 (2007) 2111

Corresponding author: Martin Steinbacher, email: martin.steinbacher@empa.ch, Tel. (+41) (44) 823 4048

PROCEEDINGS.doc

16.01.08

45 / 912nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

THE VIBRATIONAL SPECTROSCOPY OF HYDROGEN ADSORBEDON MICROPOROUS SYSTEMS.
Adriano Zecchina
UNIVERSITÀ DEGLI STUDI dii TORINO, Dipartimento di Chimica IFM and NIS-Centre of
Excellence, via P. Giuria 7, I-10125 Torino, Italia
The most recent results concerning adsorption and storage of hydrogen on high surface area materials(zeolites, MOFs, polymers both pure and functionalized)are reviewed. It is shown that vibrational
spectroscopy is a powerful tool to investigate the interaction forces governing the adsorption/desorption
processes.

Corresponding author: Adriano Zecchina, email: adriano.zecchina@unito.it, Tel. (+39) (1) 109 17860

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

DESTABILISED FLUORITE-STRUCTURED MG-BASED HYDROGEN
STORAGE MATERIALS
P.H.L. Notten1,2, P. Vermeulen1, P. Kalisvaart1, A. Ledovskikh1 and D. Danilov1
1
2

Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
Philips Research Laboratories, 5656 AE Eindhoven, The Netherlands

Introduction
It has been shown that alloying Mg with Sc
enhances the kinetics of hydrogen insertionand extraction dramatically.[1,2] It was argued
that the origin of these enhanced kinetics is
related to the favorable crystallographic
fluorite structure of the hydride.

destabilize the hydrides to a much higherhydrogen pressure of ~0.1 bar at room
temperature. Typical examples, such as
MgTiAl shown in curve (a) of Fig. 1,[7] will be
discussed together with the simulation resultsof the corresponding isotherms.[8]Results
An interesting alternative for Sc was shown
to be Ti which also forms a fluorite structure
in its elemental hydride form. Interestingly, Ti
does not form stable compounds with Mg
under standard alloying conditions but it has
recently been shown that meta-stable alloys
can be prepared using non-equilibrium
deposition methods.[3-6] These binary MgTicompounds combine a high hydrogenstorage capacity[3,4] (Fig. 1, curve (b)) withattractive optical properties.[5,6]Fig. 2. In situ electrochemical XRD of Mg0.75Ti0.25
MgTiAl (a) and MgTi (b). upon GITT

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

Fig. 1. Electrochemically determined isotherms of(dis)charging along the isotherm.

It will be shown by using in situ
electrochemical XRD measurements that
also in this case the favorable kinetics is
related to the specific fluorite structure (Fig.
2). By adding a third element to these metastable MgTi compounds we recently
succeeded, in accordance with the Miedema
rule of reversed stability, to partially

[5]
[6]

[7]
[8]

P.H.L. Notten, M. Ouwerkerk, H. van Hal, D.
Beelen, W. Keur, J. Zhou, H. Feil, J. Power
Sources,129 (2004) 45.
R.A.H. Niessen and P.H.L. Notten, J. Alloys
Comp. 404 (2005) 457.
R.A.H. Niessen and P.H.L. Notten,
Electrochem. Solid-State Lett. 8 (2005)
A534.
P. Vermeulen, R.A.H. Niessen and P.H.L.
Notten, Electrochem. Commun. 8 (2006) 27.
D.M. Borsa, A. Baldi, M. Pasturel, B. Dam,
R. Griessen, P. Vermeulen, P. Notten, Appl.
Phys. Lett., 88 (2006) 241910.
D.M. Borsa, R. Gremaud, A. Baldi, H.
Schreuders, J.H. Rector, B. Kooi, P.
Vermeulen, P.H.L. Notten, B. Dam and R.
Griessen, Phys. Rev. B., 75 (2007) 205408.
P. Vermeulen, E.F.M.J. van Thiel and P.H.L.
Notten, Chem. Eur. J., 13 (2007) 9892.
A. Ledovskikh, D. Danilov and P.H.L. Notten,
Physical Review B, 76 (2007) 064106.

Corresponding author: Peter Notten, email: peter.notten@philips.com, Tel. (+31) (40) 247 4017
PROCEEDINGS

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008SCALING UP EFFECTS OF Mg HYDRIDE AS A MATERIAL FOR
HYDROGEN STORAGE
M. Verga1, F. Armanasco1, C. Guardamagna1, C. Valli1, A. Bianchin2,
S. Lo Russo2, A.Maddalena3, G. Principi3
1

CESI RICERCA S.p.A.,Via Rubattino 54, 20134, Milano, Italy
Dipartimento di Fisica, Università di Padova, via Marzolo 8, 35131 Padova, Italy
3
Settore Materiali, Dipartimento di Ingegneria Meccanica, via Marzolo 9, 35131 Padova, Italy
2

A research program addressed to evaluate the magnesium hydride storage potentiality in stationary
applications is being developed in the frame of a collaboration between CESI RICERCA, Milano, and theHydrogen Group of Padova University. As a first step of scale-up effects evaluation, that are of major
importance in industrial components, a storage system containing 500g of magnesium hydride powder(manufactured, using high energy ball milling, by Venezia Tecnologie SpA) has been designed and tested
in different operating conditions in a fully automated test facility. The geometry design of the storage
system has been carried out with the aim of ensuring a good heat exchange in order to overcome the low
thermal conductivity of the hydride powder. A series of absorption and desorption cycles at different
temperatures and pressures has been tested and the results have been compared with laboratory dataobtained on small amounts (fraction of g) of powder samples. During the first cycles the behaviour of thescaled up system was rather similar to that of laboratory samples: maximum storage capacity of 5.35 wt%
and hydrogen absorption and desorption kinetics slightly worse. Important thermal effects characterised by
local powder heating has been noticed; a sensible performance degradation has been recorded after
about 20 cycles, presumably due powder fragmentation and subsequent compaction that reduced theoverall storage capacity of about 50%. Subsequent tests on a smaller storage system equipped also withporous baffles gave useful indication for the design of an improved large storage system.

Corresponding author: Giovanni Principi, email: giovanni.principi@unipd.it, Tel. (+39) (49) 827 5513
PROCEEDINGS

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

COMBINED PLATINUM / PEROVSKITE CATALYST FOR AN
EFFICIENT NANOSTRUCTURED AIR ELECTRODE
Doreen Thiele, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
By combining platinum and the two perovskites La0.6Sr0.4CoO3 (LSC) and La0.65Sr0.35MnO3 (LSM) on acarbon nanotube (CNT) support air electrodes for fuel cells or zinc air batteries are produced, having fewer
losses than a conventional Pt electrode. It is possible to reduce the amount of Pt up to 62 % compared toa conventional “Pt on carbon” electrode, which implies cost reductions up to 57 %. LSC has a positive
impact on the activation polarization and LSM on the concentration polarization.

Introduction
In this work we demonstrate that a combined
catalyst of LSC and LSM perovskites and Pt
on a carbon nanotube support displays asmaller polarization in the whole current
range than a conventional “Pt on carbon”
electrode, although considerably less Pt isused.

The addition of Pt is necessary to competewith conventional “Pt on carbon” electrodes.
However, up to 62 % Pt can be saved and anelectrode which is superior in the wholecurrent region is obtained. The addition ofsmall amounts of LSM (5 - 10 wt%) lowers
the concentration polarization compared tothe electrode consisting of LSC, CNTs andPt.

Experimental
LSC and LSM perovskites, Pt on carbon,
CNTs, PTFE dispersion and distilled water
were mixed ultrasonically. After drying theresulting powder was sintered at 350 °C for 2
hours. Then the powder was mixed withpetroleum to make a paste which was spreadon teflonized Toray Carbon Paper, serving as
gas diffusion layer. The two layers, catalytic
active layer and gas diffusion layer, werepressed together and heated to 320 °C for 1
hour. A three electrode arrangement waschosen to measure the steady state current
potential curves in alkaline solution.

Fig. 1. Steady state current potential curves of airelectrodes with different compositions.

Results
As shown in Fig. 1 the addition of Pt lowers
the activation polarization at low current
densities significantly compared with theelectrode composed only of LSC and CNTs.

References[1]

Norskov et al; J. Phys. Chem. B 108 (2004)
17886

Corresponding author: Doreen Thiele, email: doreen.thiele@empa.ch, Tel. (+41) (44) 823 4082

PROCEEDINGS

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

A Cu/Pt NEAR-SURFACE ALLOY FOR WATER-GAS SHIFTCATALYSIS STUDIED BY STM, XPS, TPD, AND DFT
Ronnie T. Vang, Jan Knudsen, Joachim Schnadt, and Flemming Besenbacher.
Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy,
University of Aarhus, Denmark.
The water-gas shift (WGS) reaction, in which carbon monoxide (CO) and water (H2O) react to form carbon
dioxide (CO2) and hydrogen (H2), is an important step in the production of clean (CO free) hydrogen fromfossil fuels. WGS catalysis is also an integral part of the onboard reforming of, e.g., methanol in low
temperature fuel cell vehicles. For such mobile applications weight and volume is a critical issue, and it
remains a challenge to design WGS catalysts with high activity at low temperature and thereby reduce theoverall size of the reforming units.

In this study we use a combination of
scanning tunneling microscopy (STM), x-ray
photoelectron
spectroscopy(XPS),
temperature programmed desorption (TPD),
and density functional theory (DFT) to study
a bimetallic Cu/Pt model catalyst for the
WGS reaction [1]. From STM, XPS, and DFT
we find that when Cu is evaporated ontoPt(111) at high temperature (800 K) athermodynamically stable surface alloy isformed. The topmost atomic layer in thissurface alloy consists purely of Pt, and theCu atoms are embedded in the subsurface
layers with the highest Cu concentration in
the first subsurface layer. The TPD
measurements show that the subsurface Cu
atoms weaken the binding of CO to the
topmost Pt layer, thus minimizing the risk of
CO poisoning of the surface. Thisobservationisconfirmed
byDFT
calculations.
Furthermore,theDFT
calculations show that the Cu/Pt(111) surface
alloy effectively activates water, while onlybinding the reaction products (CO) andreaction intermediates (formate) weakly.
Water activation is the rate limiting step in
WGS on several transition metals including
Cu and Pt, and the DFT calculations
therefore suggest that the bimetallic Cu/Pt
catalyst is a promising candidate for an
improved WGS catalyst.

References[1]

J. Knudsen, A. U. Nilekar, R. T. Vang, J.
Schnadt, E. L. Kunkes, J. A. Dumesic, M.
Mavrikakis and F. Besenbacher, J. Am.
Chem. Soc., 2007, 129, 6485-6490.

Corresponding author: Ronnie T. Vang, email: rtv@inano.dk, Tel. (+45) 8942 5538

PROCEEDINGS

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

THIN-FILM ELECTROCATALYSTS FOR PEM FUEL CELLS
Björn Wickmana, Henrik Ekströmb, Marie Gustavssona, Göran Lindberghb, Per
Hanarpa and Henrik GrönbeckaaCompetence Centre for Catalysis, Department of Applied Physics, Chalmers University ofTechnology, SE-412 96 Göteborg, Sweden. bApplied Electrochemistry, School of Chemistry andChemical Engineering,Kungliga Tekniska Högskolan (KTH), SE-100 44 Stockholm, Sweden.
Fundamental processes in PEM fuel cells are studied by use of well-characterized nanometer-thickcatalyst films deposited on Nafion membranes or gas diffusion layers. The activity for oxygen reduction
reaction, stability and proton conduction is evaluated for platinum in combination with a range of metals
and metal-oxides in a single cell set-up. In addition, the samples are structurally and chemicallycharacterized with TEM, SEM and XPS.

Introduction
The catalyst material in the PEM fuel cellneeds to be improved with respect toperformance and durability. Well definednanostructures are convenient model
systems to study governing mechanisms.
Recently, we have developed a route to
manufacture model systems in a fast andrelatively easy manner, with high control overstructure and composition. The samples are
possible to evaluate under realistic fuel cell
operating conditions in a real fuel cell.

Experimental
Nanometer thick catalyst films (~5-10µg/cm2) have been deposited on to Nafion
membranes and gas diffusion layers by
thermal evaporation in vacuum. A large
range of catalyst materials have been tested
including Pt mixed with Au, Ir and TiO2. The
morphology and composition of the thin films
are thoroughly characterized with TEM, SEM
and XPS.

Results
The thin-film model system can be used toqualitative compare and rank catalystmaterial in the PEMFC environment. Clearchanges in the catalytic and structuralproperties of Pt were observed when themetal was mixed in bi-layers with Ir and TiO2.
TiO2 was found to operate as a proton
conducting electrolyte in the PEMFC.

Fig. 1. Polarization plots in O2 and CV in N2 forcatalyst films deposited on Nafion.

In addition, adding TiO2 between Pt and thecarbon gas diffusion layer indicated anincreased durability of the PEMFC electrode.

References[1][2]

Ekström et al; Electrochimica Acta 52 (2007)
4239
Gustavsson et al; J. Power Sources 163(2007) 67

Corresponding author: Björn Wickman, email: bjorn.wickman@chalmers.se, Tel. (+46) 317725179

PROCEEDINGS

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

HIGH-THROUTHPUT AND COMBINATORIAL METHODS USED FOR
HYDROGEN TECHNOLOGIES. DESIGN OF CATALYSTS FOR
PRODUCTION AND PURIFICATION OF HYDROGEN.
András Tompos1, József Margitfalvi1,2, Lajos Végvári2
1

Institute of Surface Chemistry and Catalysis, H-1025 Budapest, Hungary,
Nanotech Kft. H-1122 Budapest, Hungary

2

Combitech-

Different catalyst libraries were designed and tested for hydrogen production via ethanol reforming and for
CO removal from hydrogen containing gas mixture (PROX). Multi-component gold based supported
catalysts over MgO and Al2O3 were designed for PROX application. In ethanol reforming Pd, Ni, and Co
based catalysts were tested. In PROX modification of the support by Pb, Sm, Ba, Ce and V resulted invery active and selective catalysts. The optimum composition of catalysts strongly depended on the type of
support and the mode of pre-treatment prior to the reaction.

Introduction
Hydrogentechnologies
requirenewmaterials, such as catalysts, adsorbents,
membranes etc. The use of high-throughput
and combinatorial methods (HTCM) strongly
increases the change to find these materials.
In this work results obtained in various casestudies related to design of new catalysts will
be given.

Sm and V as modifiers. The visualization ofthese experimental spaces is given in Fig 1.

Experimental
The high-throughput reactor setup applied is
described elsewhere [1]. HRS and its
combination with ANNs as an information
mining tool [2] was used for catalysts design.
Urea method was applied for the preparationof multi-component supports and theintroduction of gold. Reduction in hydrogen at
350 oC was used as a general pretreatment
procedure, what was also combined by more
complex pretreatment procedures.

Fig. 1. Visualization of the experimental space in
PROX reaction over modified Au/MgO catalysts

The alumina support required completely
different modifiers, such as Pb, Cu, Ba, Ag
etc. Results unambiguously show theadvantage of HTCM in catalyst development
for hydrogen technologies.

Results

References

In PROX two methods for catalysts pretreatment were compared. After reductive
treatment the optimum catalyst contained Au,
Pb, Sm, Ce, Y and La, while after combined
reductive treatment the Au required only Pb

[1]
[2]

Végvári, et al; Catal. Today 81 (2003) 517
Tompos, et al; Appl. Catal. A Gen. 254(2003) 161

Corresponding author: András Tompos, email: tompos@chemres.hu, Tel. (+36) (1) 438 1163
PROCEEDINGS

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

PHOTOCATALYTIC
WATER
GRAPHITE/ICE INTERFACE

DISSOCIATIONAT

Dinko Chakarov, Johan Bergeld, Bengt Kasemo
Dep. of Applied Physics, Chalmers University of Technology, S-41296 Göteborg, Sweden
We have studied the photodissociation of water molecules at the ice/graphite interface in thepresence of submonolayer amounts of potassium at UHV conditions. The ice films aretransparent for 240 – 900 nm photons, but the strong light absorption of graphite substrate
generates energetic charge carriers that may drive photoreactions at the interface. Similar
schemes have been demonstrated and investigated before in the monolayer regime1. Here,using ice films of tens of monolayer thickness and with different structure, we investigate theconfinement effects due to the ice layer, and the ice permeability for reaction products.

Introduction
Significant fraction of visible light has enoughenergy to split H2O into hydrogen andoxygen. However, water is transparent in thevisible and does not absorb this energy. The
combination of a light harvesting system anda H2O splitting system is thus necessary. We
are exploring a graphite substrate, covered
with small amounts of alkali atoms, because
it is an interesting model system forphotoreactions at surfaces and in particular
H2 production.

immediately upon irradiation. The proposedmechanism is schematically illustrated on
Fig. 1. Central for this study2 was to elucidate
the role of ice structure on reaction outcome.
While CO and CO2 were trapped by(poly)crystalline ice, H2 is able to permeate
through both amorphous and annealed films.
CO and CO2 were still generated under theice cover during the irradiation and released
later when the ice (re)crystallizes or
sublimates. Some of the reaction products
could be trapped inside the ice.

Experimental
The experiments were performed at ultrahigh vacuum conditions in the low 10-10 mbar
range. The ice films were grown on the basal
plane of highly oriented pyrolytic graphite at
LN2 temperatures. Irradiation was performedin either pulsed or continuous (cw) regime
using
Nd:YAG
laser
pumpedOPO(Continuum) system, or short arc lamp
system (PI). For detection and direct
monitoring of the photodesorbing products
we used quadrupole mass spectrometers.

Results
H2, CO and CO2 were seen as main
desorbingphotoreaction
products

Fig. 1. Mechanism ofwater molecule
photodissociation in presence of K+ on graphite.

References[1][2]

D. Chakarov, M. Gleeson, and B. Kasemo, J.
Chem. Phys., 115, 9477 (2001).
J. Bergeld, B. Kasemo, D. Chakarov, Phys.
Chem. Chem. Phys., 2008, 10, 1–5.

Corresponding author: Dinko Chakarov, email: dinko.chakarov@fy.chalmers.se, Tel. (+45) (31) 7723375

PROCEEDINGS

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

HY.MUVE – HYDROGEN DRIVEN MUNICIPAL VEHICLE
Peter Schlienger, Martin Weilenmann, Jean-Yves Favez, Christian Bach, Felix
Büchi
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec. I.C.
Engines, CH-8600 Dübendorf, Switzerland
Municipal vehicles (road sweepers) are an ideal platform for the early introduction of fuel cell power trains
for various technical and non-technical reasons, among them: for most of the time (in cleaning mode)these vehicles run at low loads, where fuel cells are highly efficient. As operation is local, a small hydrogen
infrastructure is sufficient, “zero emissions” allow use in closed areas as shopping malls or train stations
and as operation takes place in public, high visibility and publicity is possible. In the Hy.muve project aroad sweeper will be equipped with a fuel-cell-hybrid drive train and run in practice for 18 months. This
allows gaining knowledge in complex drive train layout, practical realisation questions, real world ageing offuel cells and socio-economic aspects of development, production, usage and public awareness.

•••

50% energy consumption reduction
compared to existing diesel vehicle. I. e.
less than 7.5 kg of hydrogen used forone 8 hour shift.
Pre series demonstrator running 18
months in practice in 3 cities.
Socio-economic research regarding new
production channels, market preparationand introduction of H2 powertrains.

By optimising fuel cell and battery size, a fuelconsumption of less than 5 kg of hydrogen
was achieved.

Well to wheel estimation
As in this application the fuel cell runs nearits best point for long phases, a well to wheel
analysis even assuming the today’s non
optimal H2 production out of natural gas
shows that this fuel cell approach is superior
to CNG-electric or diesel electric drive trains.

Drivetrain layout and optimisation
The originally hydraulic drive trains of traction
chain and vacuum-ventilator are electrified
for better efficiency
The fuel cell is hybridized with a battery forrecuperating energy while breaking or driving
downhill.

Well-to-wheel energy use in MJ/a and CO2 emissions in kg/a
40

400 MJ/a
WtW Energy [MJ/a]

WtW CO2 [kg/a]
35

350 MJ/a
300 MJ/a287 MJ/a

272 MJ/a

250 MJ/a
203 MJ/a

30
25

218 MJ/a

20

200 MJ/a21.6 kg/a

15

150 MJ/a
16.5 kg/a
100 MJ/a

16.0 kg/a

10

11.6 kg/a

Efficiency optimisation
To optimise the drive train components to an
overall best efficiency, a characteristic load
cycle for a one day shift was developed byassistance of operators in different cities of
Switzerland. This test cycle contains a speed
diagram, a slope distribution and arealistically growing load of the vehicle. In the
speed diagram three dislocation phases of
30 min and 6.5 hour of cleaning areassumed.

5

50 MJ/aWTW-CO 2-Emissionen in kg/a

Project goals

0

0 MJ/aDieselhydraulic drive(55 kW)

Fuel cellelectric drive(30 kW)

Diesel electric drive CNG electric drive
E-Antrieb

Fig. 1. Comparison of well to wheel energy
consumption and CO2 production.

References[1]

Weilenmann et al; ICPC Graz. 2007

Corresponding author: Peter Schlienger, email: peter.schlienger@empa.ch, Tel. (+41) (44) 823 4671

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

THERMAL PROPERTIES OF Mg(BH4)2 DOPED WITH TRANSITIONMETAL CHLORIDES
Elisa Gil Bardají, Nobuko Hanada, Christoph Frommen and Maximilian Fichtner
Institut für Nanotechnologie, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe,
Germany
Hydrogen storage materials based on complex hydrides, such as tetrahydroaluminates, tetrahydroborates,[1-3]
Materials consisting ofand amides, have been considered promising for reversible hydrogen storage.
light elements have also drawn attention due to the high gravimetric storage capacities for hydrogen andespecially, Mg(BH4)2 seems to meet the requirements for hydrogen storage material because it contains[4, 5]
14.9 mass % and has suitable thermodynamics properties.
The main disadvantages of Mg(BH4)2 as hydrogen store is the high absorption/desorption kinetic barriers.
Transition metal compounds such as MCl3 (with M = V, Ti, Mo, Ce) were added to Mg(BH4)2 in order tolower these kinetics barriers. X-ray diffraction measurements (XRD) and thermogravimetric analysis (TGADSC) of the samples after mechanical ball-milling will be presented.

References

[3]

[1]

[4]

[2]

B. Bogdanović and M. Schwickardi, J. Alloys
Compd. 253-254 (1997), pp. 1.
A. Züttel, S. Rentsch, P. Fischer, P. Wenger,
P. Sudan, P. Mauron and C. Emmenegger,
J. Alloys Compd. 356-357 (2006), pp. 515[5]

P. Chen, Z. Xiong, J. Luo, J. Lin and K. L.
Tan, Nature 420 (2002), pp. 302.
K. Chlopek, C. Frommen, A. Léon, O.
Zabara and M. Fichtner, J. Mater. Chem. 17(2007), 3496-3503.
H.-W. Li, S. Orimo, Y. Nakamori, K. Miwa, N.
Ohba, S. Towata and A. Züttel, J. Alloys
Compd. 315-318 (2007), pp. 446,

Corresponding author: Elisa Gil Bardají, e-mail: elisa.gil@int.fzk.de, Tel. (+49) (7247) 82 2680
PROCEEDINGS

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2nd Hydrogen & Energy Symposium

IMPROVING RHCMILLING

Braunwald, Switzerland 2008

COMPOUNDS PREPARATION BY BALL

S. Garronia,1, S. Suriñacha, M.D. Baróaa

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

1

Sebastiano.Garroni@campus.uab.cat

The NaBH4 is one of the light-complex hydrides most studied in the field of hydrogen storage. It has a hightheoretical hydrogen capacity of 10.8 wt% and it is relatively cheap. But, its decomposition temperature isclose to 400°C and the destabilization of NaBH4 by ball milling is also very difficult because it is quite
resistant to formation of nanostructure. Nevertheless, the destabilization of this compound can be obtainedby the addition of reactive hydrides, such as MgH2. This approach can be utilized also for others complex
hydrides. It generates a new class of compounds called “Reactive Hydride Composites”, which are
obtaining a great interest as a new potential hydrogen storage material.

This work presents a systematic study of the
RHC basis NaBH4 preparation by two
different milling machines.
In order to provide a basis of comparison forthe milling process with either Spex 8000 or
Fritsch Planetary milling device, the powdersof NaBH4 + MgH2 have been mixed in a ratioof 2:1 under Ar for 5 hours with the ball-topowder (BPR) weight ratio of 10:1. A further
preparation has been carried out in the same
milling conditions, except for the addition ofan additive. Thermal and structural properties
have been investigated by Differential
Scanning Calorimetry (DSC) and X-ray

Diffraction(XRD),
respectively.
Microstructure has been studied using
Scanning Electron Microscopy (SEM). The
hydrogen desorption after milling has beenmonitored by Integrate Microbalance System(IMS) integrated with a mass-spectroscopy.
With the purpose to optimize the preparation
methods for the RHC samples, thecorrelation between the particles andcrystallites size and the desorption
temperature is discussed. A comprehensive
structural study at different temperatures
regarding the sample milled with an additiveis here presented.

Corresponding author: Sebastiano Garroni, e-mail: sebastiano.garroni@campus.uab.cat, Tel. (+34) (954)489 531

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2nd Hydrogen & Energy Symposium

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MICROSTRUCTURAL AND CHEMICAL STUDY OF 2LiBH4+MgH2
REACTIVE HYDRIDE COMPOSITE FOR H2 STORAGE
E. Deprez1*, A. Justo1, D. Martínez-Martínez1, T. C. Rojas1, A. Fernández1, U.
Bösenberg2, M. Dornheim2, R. Bormann2
1

Instituto de Ciencia de Materiales de Sevilla, CSIC-Univ.Seville, Avda. Américo Vespucio 49,
41092 Seville, Spain.
2

Institut für Werkstoffforschung, GKSS Forschungszentrum, 21502 Geesthacht, Germany

Hydride composite systems reveal great potential as hydrogen storage materials as they overcome thethermodynamic limitations hindering the use of light-weight complex hydrides. In the present
communication the effect of Ti-based additive has been studied in the system 2LiBH4 + MgH2. The
microstructure is characterized by X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM)in the milled and cycled states.

X-Ray diffraction in transmission
mode has been used to identify the
crystalline phase present in the samples.
Moreover, the microstrain and the crystallite
size of the different phases were calculatedby the Williamson-Hall method.
The materials were observed byTransmission Electron Microscope formicrostructure analysis. Energy Dispersive
X-Ray Analysis (EDX) was used to determine
the elements present in the samples andElectron Energy Loss Spectroscopy (EELS)
to register the energy loss spectra of Boron,
Oxygen and Titanium and determine thelocation of the Titanium based additive in thesample.
For both samples after milling, the
LiBH4 showed larger crystal size than MgH2.
Besides, the microstrain is found to be oneorder of magnitude larger for both phases
milled with the additive. After desorption, thissample evolves to a mixture of LiH and MgB2
phases with reduced levels of microstrain.
The crystal sizes of both phases are found tobe similar, and intermediate between theones of the preceding LiBH4 and MgH2
phases. The crystal sizes of the desorbed
products in presence of additive are smaller
than the ones of the desorbed from
2LiBH4+MgH2 milled without additive.
The
first
resultsfrom
TEM
investigations coupled with EDX and EELS
show in the composite materials 2LiBH4 +MgH2 two regions: one mainly consisting of
Mg and a second one which appears to beamorphous and is containing a high amountof Boron.

Corresponding author: Emilie Deprez, e-mail: emilie.deprez@icmse.csic.es, Tel. (+34) (954) 489 531
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IN-SITU MONITORING DURING SYNTHESIS OF LiBH4 AND
Mg(BH4)2 BY BALL MILLING UNDER DIFFERENT PRESSURESAND ATMOSPHERES
Isabel Llamas Jansa, Carine Rongeat, Oliver GutfleischLeibniz Institute for Solid State and Materials Research Dresden, Institute for Metallic Materials, P.O. Box.
270116, D-01171 Dresden, Germany
The synthesis of LiBH4 and Mg(BH4)2 by ball milling under different pressures and atmospheres wasmonitored by means of dedicated milling vials. This allowed the tuning of parameters such as ball-topowder ratio, initial pressure, milling duration and catalyst addition. The synthesis of LiBH4/MgH2
composites from a mixture 2LiH + MgB2 was expected to occur under high-pressure reactive milling,whereas the synthesis of Mg(BH4)2 from a mixture 2LiBH4+MgCl2 was expected to occur already under 1
bar Ar. The efficiency of TiCl3 and Ti-isopropoxide as catalysts for these reactions was studied. X-ray
powder diffraction and Raman spectroscopy of the as-milled powders were carried out to confirm the dataobtained during synthesis.

Introduction
Borohydrides
haverecently
received
increasing attention as potential materials foron-board hydrogen storage. The aim of thepresent work is the formation of LiBH4/MgH2
composites and Mg(BH4)2 by ball millingunder different pressures and atmospheres.

Experimental
Starting mixtures of 2LiH + MgB2 and 2LiBH4+ MgCl2, with and without catalyst, weremilled together with stainless steel balls (10mm Ø) at different ratios. The initial millingpressure was chosen between 1 bar Ar, and
1 and 135 bar H2 at room temperature. The
milling duration was varied from 5 to 20 h.
The reactions occurring during milling weremonitored by means of specially designed
vials (by Evico Magnetics). Pressure (p) andtemperature (T) variations were recorded [1].
The as-milled powders were characterised by
X-ray powder diffraction (XRD) and Raman
spectroscopy.

Results
In the case of 2LiH + MgB2, the results
showed almost constant p and T curves forthe samples milled with no catalyst or with Tiisopropoxide under initial pressures of 50 bar
H2. This indicated that no reaction was taking
place between the compounds and thesurrounding H2 under these conditions. In
contrast, the samples milled with TiCl3
showed a distinctive pressure decrease
occurring after 2.5 h of milling. The decrease
was found to be stronger in the case of thesample milled under 135 bar H2. The
diffraction pattern of the resulting powder
showed no traces of LiBH4 or MgH2, but thepresence of small amounts of LiCl, and theabsence of strong LiH traces, indicated thatat least a portion of the TiCl3 reacted with LiH
during the process. On the other hand, theball milling of 2LiBH4 + MgCl2 mixtures under
1 bar Ar, showed no identifiable features on
the monitored curves. In the case of asample milled for 12 h, the XRD traces of
LiBH4 and MgCl2 were found to disappear
whereas a Li-Mg-Cl phase with the structureof LiCl was identified. Although no traces ofMg(BH4)2 were identified by XRD, Raman
spectroscopy confirmed the partial formationof magnesium borohydride consistent withthe results by Nakamori et al. [2] andMatsunaga et al. [3].

References
[1]
[2]
[3]

Doppiu et al; J. Alloys Comp. 427, 204(2007)
Nakamori et al; Physical Review B 74,
045126 (2006)
Matsunaga et al; J. Alloys Comp. in press

Corresponding author: Isabel Llamas Jansa, email: i.llamas.jansa@ifw-dresden.de, Tel. (+49) (351) 4659 669

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2nd Hydrogen & Energy Symposium

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Li[BH4] AND Li[BD4] SYNTHESIS FROM Li-B ALLOY
Oliver Friedrichs, Arndt Remhof, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The direct synthesis of Li[BD4] and Li[BH4] from the corresponding elements is demonstrated. For the
Li[BD4] the formation was achieved at T = 350°C and p(D2) = 180 bar. The chemical inertness of boron isthought to prevent its reaction with lithium and deuterium/hydrogen to Li[BD4]/Li[BH4] at lower
temperatures. We show however that the reaction kinetics can be enforced by a LiB3 like alloy which isformed in inert argon atmosphere at 330°C. The synthesis of the boranate is carried out by exposing the
Li-B alloy to a defined deuterium/hydrogen pressure in a high pressure stainless steel vessel and theadsorption is monitored by the pressure decrease in the system (for the Li[BH4]) or by “in situ” neutron
powder diffraction (for the Li[BD4]).

Introduction
In this work an improved direct synthesis of
Li[BD4]/Li[BH4] from the elements ispresented based on a preceding formation of
a LiB3 alloy [1-2]. An analysis of theabsorption reaction is performed in order todescribe the mechanism. Thereby “in situ”
neutron diffraction is applied to study theabsorption process.

accomplished by a pre-formation of a LiB3
alloy heating Li and pre-milled boron in inert
gas atmosphere. The hydrogen uptake andneutron diffraction measurements during
heating of the LiB3 alloy in H2/D2 reveal
different reactions of boranate formation
taking place (see Fig. 1). These reactions aretemperature dependent.
Li

Experimental

B
330 °CAr

The starting material for the synthesis is a
mixture of Li and pre-milled B of
stoichiometric ratio 1:3. Heating the Li/B
mixture for 60 h at 330°C in Ar atmosphereleads to the formation of a LiB3 alloy [3]. The
samplewasthenheatedindeuterium/hydrogen from room temperature(RT) to 700°C (for H2) or from RT to 500°C(for D2) in a high pressure stainless steel
cylinder. For the hydrogen sample thehydrogen uptake was monitored by thepressure changes in the system and for the
deuterium sample neutron diffraction patterns
were taken for different temperatures.

Fig. 1. Mechanism of the Li[BH4] formation.

Results

References

We demonstrated the preparation of solvent
free Li[BD4] and [Li[BH4] from the elements.
For the Li[BD4] the synthesis was achieved ata deuterium pressure of 180 bar and atemperature of 350°C. This improvement is

[1]
[2]
[3]

200 °C

LiH

LiB3

200 °CB

350 °C

500 °C

LiBH4500 °CH2

At lower temperatures (200°C) LiD/LiH and B
is formed. Then with increasing temperatures(350°C) a direct formation of the boranatefrom LiB3 starts. At higher temperatures(500°C) the Li[BD4]/ Li[BH4] is generated
from LiD/LiH and B.

Friedrichs et al., Acta Materialia, in press
Remhof et al., to be published
Meden et al.; J. Phys. Chem. 99 (1995) 4252

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

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2nd Hydrogen & Energy Symposium

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MASS FLOW METHOD FOR THE CHARACTERIZATION OF
HYDROGEN SORPTION KINETICS
Shunsuke Kato, Michael Bielmann, Andreas Borgschulte, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The mass flow measurement can be used for the thermodynamic characterization, ∆H and ∆S, ofhydrogen storage materials by determining equilibrium pressures at zero-flow. Moreover, flow
measurements provide information about reaction kinetics. In this work, hydrogen desorption kinetics by
LaNi5 was measured at 293 K. The result indicates that the mass flow method is of great use in kinetic
characterization and to explore future hydrogen storage materials.

Introduction
With a conventional volumetric method, i.e.,
Sieverts’ type apparatus, a slow reaction ratecausessignificant
difficultyinthedeterminationof
p-c-isotherms
andthermodynamic properties due to a longreaction time and the incidental systemerrors. A MF (Mass flow) measurement
which gives dynamic p-c-isotherms isadvantageous to a slow-kinetic material andcan be applied to the thermodynamic
characterization, namely, for van’t Hoff plot
with equilibrium pressures extrapolated tozero flow rate [1, 2]. On the principle, a MFmethod gives kinetic information and canalso be utilized for reaction kinetic study. In
this work, desorption measurement of LaNi5
was demonstrated.

Experimental
The sample was activated by 16 hydridingdehydriding cycles prior to the subsequent
measurements. A Mass flow controller wasused to calculate the amount of hydrogenevacuated during a desorption measurement.
BET surface area was measured after aseries of the measurements. Reaction
probability (i.e. recombination probability fordesorption process), which is defined as theratio of the reaction rate to the impinging rateof hydrogen molecules, was used for theassessment of the reactivity of hydrogenmolecules on the sample surface [3].

Results
Desorption measurement of LaNi5 revealed
that the MF-method is of great use in the
kinetic study, especially, focusing on aplateau region of the p-c-isotherm. This work
exhibits potential to access information about
the surface properties of hydrogen storage
materials.

References
[1]
[2]
[3]

To be presented by Michael Bielmann, 2ndHydrogen & Energy Symp., Braunwald,
Switzerland, 2008.
Phlippe Mauron, et al, J.Phys.Chem. B(2007), in press.
H.Uchida, Int.J.Hydrgen Energy 24 (1999)
861.

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

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2nd Hydrogen & Energy Symposium

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THERMOGRAVIMETRY OF Li[BH4]
Flavio Pendolino, Andreas Borgschulte, Andreas Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec. 138
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The magnetic suspension balance allows the thermogravimetry measurements of hydrides. The control oftemperature, pressure and mass takes place simultaneously and with high accuracy. As a first example it
presents the thermogravimetry of LiBH4.

50

100

50

100

150

200

250

200

250

300

350

400

450

350

400

450

0.0
-0.1
-0.2
-0.3
0
-2
-4
-6
-8
-10
-12
-14

melting

In the suspension balance the sample is nothanged directly at the balance but it links to a“suspension magnet”. This consists of apermanent magnet, a sensor core and a
device for decoupling the measuring load
and it is freely suspended state maintainedby an electromagnet controlled via electronic
unit. Sample handing takes place in an Arglove box. The microbalance is locatedoutside the argon box and measures theforce transmitted by magnetic suspension
coupling inside the measuring chamber.

The kinetics can be studied by measuring themass of the sample at constant temperatureand pressure changing or at constantpressure and varying the temperature (socalled thermodesorption spectroscopy)

phase transformation

Setup

Kinetics

dm/dt (mass%/min)

The magnetic suspension balance is able todetermine the equilibrium pressure bymeasuring the mass with high accuracy
under controlled conditions of temperatureand pressure. From this it is possible tocalculate the heat of formation.
The
thermodynamic and kinetic aspects can bestudied.

m (mass %)Introduction

150

300

temperature (deg C)

Fig. 2 Thermodesorption of LiBH4 in bar hydrogen.
Heating rate is 1 K/min.

The Fig. 2 shows the thermodesorption
spectra of LiBH4 in 1 bar of hydrogen. Fromthe mass change (bottom panel) thedesorption rate (top panel) is derived.
Significant rates are observed at melting
point (268 °C) and the desorption process iscompleted in the second step at 400°C.

Fig. 1 Magnetic Suspension Balance

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

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2nd Hydrogen & Energy Symposium

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STABILITY OF Na[BH4]P. Martelli, Ph. Mauron, A. Borgschulte, A. Züttel
Empa Materials Science and Technology, Dept. Energy, Environment & Mobility, Sec.
Hydrogen & Energy, CH-8600 Dübendorf, Switzerland
The stability of NaBH4 was investigated by pcT- (pressure, concentration, Temperature) measurements
under constant hydrogen flows and extrapolated to equilibrium. From Van ‘t Hoff equation the following
thermodynamic parameters are derived fore desorption: enthalpy of reaction ∆rH = 108 kJ mol-1 H2 and-1entropy of reaction ∆rS = 133 J K mol-1 H2. NaBH4 decomposes to NaH + B + 3/2 H2 and cantheoretically release 10.7 wt% of hydrogen for this reaction.

Introduction
In this work the enthalpy ∆rH and entropy ∆rSof reaction of the desorption of NaBH4 were
determined by pcT-measurements. The
logarithm of the equilibrium pressure peq
divided by standard pressure p0 = 1.01325
bar as a function of the inverse temperatureis represented in a Van ‘t Hoff plot and ∆rH
and ∆rS are determined according to the Van‘t Hoff equation:= 108 kJ mol-1 H2 and entropy of reaction ∆rS= 133 J K-1 mol-1 H2. The decomposition
temperature as derived from the presented
pcT measurements T = 536°C is in good
agreementwiththatderivedfromthermodesoprtion T = 565°C (from [2], [3]).

p  ∆ H 1 ∆ S
ln eq  = r ⋅ − r
R TR p0 

The slope of the straight line is proportionalto ∆rH the axis intercept is proportional to∆rS.

Experimental
For the pcT measurements 250 mg of NaBH4
from Sigma-Aldrich were heated totemperatures between 600°C and 700°C
under a pressure of 1 bar hydrogen. The
measurements were performed at different
constant hydrogen flows of 0.5, 1 and 2 nccm
respectively.

Fig. 1. Van ‘t Hoff plot of NaBH4 (desorption).

References[1]

Results
The different plateau pressures for thedifferent temperatures and flows are shownin Fig. 1. Because the plateau pressuresdepend on the applied flow ln(pdes/p0) as afunction of the flow is extrapolated to theequilibrium (0 nccm) (black squares) [1].
From the Van ‘t Hoff equation the following
values were found: enthalpy of reaction ∆rH

[2]

[3]

Ph. Mauron, F. Buchter, O. Friedrichs, A.
Remhof, M. Bielmann, C.N. Zwicky, A.
Züttel, Stability and Reversibility of LiBH4,
The Journal of Physical Chemistry B,
Accepted
Z.K.Sterlyadkina, O.N. Kryukova, V.I.
Mikheeva, Reaction of Sodium
tetrahydroborate with sulphur, Russian
Journal of Inorganic Chemistry, 1965
S.Orimo, Y. Nakamori, A. Züttel, Material
Properties of LiBH4 (M=Li, Na and K),
Materials Science and Engineering, 2004

Corresponding author: Pascal Martelli, email: pascal.martelli@empa.ch, Tel. (+41) (44) 823 4082

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

SCIENCE OF HYDROGEN & ENERGY AWARD
PROF. DR. LOUIS SCHLAPBACH

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.
Louis Schlapbach started his scientific work in 1970, 38 years ago, with the investigation of the Hall effect,
electrical transport and magnetic susceptibility of liquid rear earth elements like Cerium. 30 years ago in1970 he was coauthor with Busch and Waldirich on a paper about the hydrides of La-Ni compounds. LaNi5
was subsequently investigated in view of the structure, surface segregations, hydrogen occupation ofinterstitial sites and as electrode material.LaNi5 is still the base material for most of the electrochemical
applications of metal hydrides today. The work on LaNi5 was complemented by the research on FeTi.
Louis Schlapbach realized the importance of the surface composition for the hydrogen sorption process
and he was able to describe the role of the surface-active species. Furthermore, he investigated thechanges of the surface composition of LaNi5 and FeTi in oxidizing atmospheres and he found theformation of metallic clusters as superparamagnetic particles acting as the active sites in hydrogendissociation and recombination. The investigation of the surface of metal hydrides was further intensified
by means of X-ray photoelectron spectroscopy. Louis Schlapbach was the first scientist correctly
describing the activation process of a metal hydride and, furthermore, to model the chemical compositionand states of the elements in a surface profile. He also succeeded to analyze the electronic structure ofraere earth elements and their hydrides by means of photoemission spectroscopy.
In 1990 Louis Schlapbach edited the two books "Hydrogen in Intermetallic Compounds I & II" of theSpringer Sereies. The books became a very important reference for all the researchers active in the fieldof hydrides.
Louis Schlapbach's work is highly appreciated in the worldwide hydrogen community and his contribution
to the scientific knowledge is of an enormous importance. Numerous undergraduate students, PhD
students and Post Docs have been educated by Louis in solid state physics and the sciences of hydrides.
Therefore, we are very proud to award Louis Schlapbach with the second Scinence of Hydrogen & Energy
prize.

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2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

PARTICIPANTS

PROCEEDINGS

64

2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

Dr.
Michael Bielmann(talk)

EMPA
Hydrogen and EnergyÜberlandstrasse 129
CH-8600 Dübendorf

email: michael.bielmann@gmx.ch
Tel. (+41) (44) 8234342
Fax. (+41) (44) 8234022

Dr.
Andreas Borgschulte(talk)

Empa
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Dübendorf

email: andreas.borgschulte@empa.ch
Tel. (+41) (44) 8234639
Fax. (+41) (44) 8234022

Mr.
Florian Buchter(talk)

EMPA
Hydrogen & EnergyÜberlandstrasse 129
CH-8600 Dübendorf

email: florian.buchter@empa.ch
Tel. (+41) (44) 823 40 82
Fax. (+41) (44) 8234022

Dr.
Riccarda Caputo(talk)

EMPA
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Duebendorf

email: Riccarda.Caputo@empa.ch
Tel. (+41) (44) 823 4422
Fax. (+41) (44) 823 4022

Prof. Dr.
Dinko Chakarov(talk)

Chalmers University of Technology
Applied Physics
Fysikgrand 3
SE-41296 Göteborg

email:
dinko.chakarov@fy.chalmers.se
Tel. +46 317723375
Fax. +46 317723134

Prof. Dr.
Ib Chorkendorff(inv. lec.)

CINF, Technical University of Denmark
Fysikvej, Bldg. 312
DK-2800 Kgs. Lyngby

email: ibchork@fysik.dtu.dk
Tel. +45 45253170
Fax.

Dr.
Bernard Dam(inv. talk)vrije universiteit
faculty of sciencede boelelaan 1081
NL-nl-1081 hv amsterdam

email: b.dam@few.vu.nl
Tel. +31 205987917
Fax.

PhD
Stefano Deledda(talk)

Institute for Energy Technology
Physics Department
PO Box 40
NO-2027 Kjeller

email: stefano.deledda@ife.noTel. +47 6380 6087
Fax. +47 6381 0920

Ms
Emilie Deprez(poster)

CSIC-US
Nanoestructurales Materiales
Avda Américo Vespucio 49
ES-41092 SEVILLA

email: emilie.deprez@icmse.csic.es
Tel. +34 954489531
Fax. +34 954 460 665

Prof. Dr.
Peter Edwards(inv. lec.)

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

email: peter.edwards@chem.ox.ac.uk
Tel. +44 1865 272646
Fax.

Prof. Dr.
Asuncion Fernandez Camacho(talk)

CSIC-US
Nanoestructurales Materiales
Avda Américo Vespucio 49
ES-41092 SEVILLA

email: asuncion@icmse.csic.es
Tel. +34 954 489 531
Fax. +34 954 460 665

Dr.
Maximilian Fichtner(inv. lec.)

Forschungszentrum Karlsruhe GmbH
Institute of Nanotechnology
P.O. Box 3640
DE-D-76021 Karlsruhe

email: fichtner@int.fzk.de
Tel. +49 7247 82 5340
Fax.

PROCEEDINGS

65

2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

Dr.
Oliver Friedrichs(poster)

Empa
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Duebendorf

email: oliver.friedrichs@empa.ch
Tel. (+41) (44) 8234153
Fax. (+41) (44) 8234022

Mr.
Jon Steinar Gardarsson Mydral(poster)

University of Iceland
Faculty of science
Hjardarhagi 2-6
IS-107 Reykjavik

email: jsg1@hi.is
Tel. +35 46908987
Fax.

Mr
Sebastiano Garroni(poster)

Universitat Autonoma de Barcelona
Physics department
Edifici Cc (C3/210)
ES-8193 Bellaterra

email:
sebastiano.garroni@campus.uab.cat
Tel.
Fax. +34 93 5812155

Mrs.
Corinne Gianola(secretary)

Empa
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Dübendorf

email: corinne.gianola@empa.ch
Tel. (+41) (44) 823 46 92
Fax. (+41) (44) 823 40 22

Dr.
Elisa Gil Bardaji(poster)

Forschungszentrum Karlsruhe
Institut für Nanotechnologie
Postfach 3640
DE-76021 Karlsruhe

email: elisa.gil@int.fzk.de
Tel. +49 7247 82 2680
Fax. +49 7247 82 6368

Prof. Dr.
Michael Grätzel
(inv. talk)

Ecole Polytechnique Federale de Lausanneemail: michael.graetzel@epfl.chInstitute of Chemical Science and Engineering Tel. +41 21 693 3112
Faculty of Basic Science
Fax. +41 21 693 6100
CH-1015 Lausanne

Dr.
Nobuko Hanada(talk)

Forschungszentrum Karlsruhe
Institut für Nanotechnologie
Postfach 3640
DE-76021 Karlsruhe

email: nobuko.hanada@int.fzk.de
Tel. +49 7247 82 6377
Fax. +49 7247 82 6368

Dr.
Llamas Jansa Isabel(poster)

Leibniz Institute for Solid State and Materials
Institute for Metallic Materials
Hydrogen Storage, PF270116
D-1171 Dresden

email: i.llamas.jansa@ifw-dresden.de
Tel. +49 351 4659 669
Fax.

Prof. Dr.
Hannes Jonsson(inv. lec.)

University of Iceland
faculty of science
Hjardarhagi 2-6
IS-107 Reykjavik

email: hj@hi.is
Tel. +35 48923560
Fax. +35 45254632

Mr
Shunsuke Kato
(poster)

Empa
Hydrogen & EnergyÜberlandstrasse 129
CH-8600 Dübendorf

email: shunsuke.kato@empa.ch
Tel. (+41) (44) 823 4327
Fax. (+41) (44) 823 4022

Prof. Dr.
Andrej Kuznetsov(poster)

University of Oslo£Department of Physics
Sem Saelands vei 24
NO-316 Osloemail: andrej.kuznetsov@fys.uio.noTel. 4722852870
Fax. 4785222860

Mr.
Christoph Langhammer(talk)

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

email:
christoph.langhammer@fy.chalmers.s
eTel. +46 (0)31-772 30 07
Fax. +46 (0)31-772 31 34

PROCEEDINGS

66

2nd Hydrogen & Energy Symposium

Braunwald, Switzerland 2008

Dr.
Mel Frank Licker(participant)Randgold
Energy241 skinner street
ZA-1 Pretoria

email: mohakabi@yahoo.com
Tel. +27 731927771
Fax.

Mr.
Jochen Linssen(talk)

Forschungszentrum Jülich
Institute of Energy Research - STE
Wilhelm-Johen-Strasse
DE-52425 Jülich

email: j.linssen@fz-juelich.deTel. +49 2461 613581
Fax. +49 2461 613581

Dr.
Zbigniew Lodziana(talk)

Empa - Materials Science & Technology
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Dubendorf

email: zbigniew.lodziana@empa.ch
Tel. (+41) (44) 823 4083
Fax. (+41) (44) 823 40 22

Mr
Pascal Martelli(poster)

EMPA
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Dübendorf

email: pascal.martelli@empa.ch
Tel. (+41) (44) 823 4082
Fax. (+41) (44) 823 4022

Dr.
Philippe Mauron(talk)

EMPA
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Dübendorf

email: philippe.mauron@empa.ch
Tel. (+41) (44) 823 4099
Fax. (+41) (44) 8234022

Dr.
Jiri Muller(participant)IFE

email: jiri@ife.noTel. +47 63 80 61 85
Fax. +47 63 81 11 68

Dr.
Nicola Naujoks(poster)

Chalmers University
chemical physics
Fysikgränd 3
SE-412 96 Göteborg

email: nicolan@ethz.ch
Tel.
Fax.

Prof. Dr.
Peter Notten(inv. talk)Eindhoven University of Technology

email: peter.notten@philips.com
Tel. +31 40 274 2263
Fax.

Prof. Dr.
Shin-Ichi Orimo(inv. lec.)

Tohoku University
Institute for Materials Research
Katahira 2-1-1
JP-980-8577 Sendai

email: orimo@imr.tohoku.ac.jp
Tel. +81 222152093
Fax. +81 222152091

Mr
Flavio Pendolino(poster)

EMPA
Hydrogen & EnergyÜberlandstrasse 129
CH-8600 Dübendorf

email: flavio.pendolino@empa.ch
Tel. (+41) (44) 8234776
Fax. (+41) (44) 8234022

Prof. Dr.
Cor Peters(talk)

Delft University of Technology
TNW/DCT/PCMTJulianalaan 136
NL-2628 BL Delftemail: C.J.Peters@tudelft.nl
Tel. +31 152782660
Fax. +31 152784289

Prof. Dr.
Giovanni Principi(talk)

Universit di Padova
Settore Materiali, DIM
Via Marzolo 9
IT-35131 Padova

email: giovanni.principi@unipd.it
Tel. +39 049 827 5513
Fax. +39 049 827 5505

PROCEEDINGS

Kjeller
NO-2007 Kjeller

Chopinlaan 14
NL-5583 XV Waalre67

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Dr.
AJ Ramirez-Cuesta(talk)

Rutherford Appleton Lab
ISIS Facility
Room 1-42, Bldg R3
GB-OX11 0QX Chilton

email: a.j.ramirez-cuesta@rl.ac.uk
Tel. +44 1235 44 6510
Fax.

Dr.
Arndt Remhof(talk)

Empa
Hydrogen & EnergyÜberlandstrasse 129
CH-8600 Dübendorf

email: arndt.remhof@empa.ch
Tel. (+41) (44) 8234369
Fax. (+41) (44) 8234022

Dr.
Jan Rossmeisl(inv. talk)Technical University of Denmark
CAMD-Department of Physics
Building 311
DK-2800 Lyngby

email: jross@fysik.dtu.dk
Tel. +45 45253166
Fax.

Prof. Dr.
Louis Schlapbach(inv. lec.)

Empa
Direktion
Ueberlandstrasse 129
CH-8600 Dübendorf

email: louis.schlapbach@empa.ch
Tel. (+41) (44) 823 4500
Fax.

Dr.
Peter Schlinger(talk)

Empa - Materials Science & Technology
Laboratory for Internal Combustion EnginesÜberlandstrasse 129
CH-8600 Dübendorf

email: peter.schlienger@empa.ch
Tel. (+41) (44) 823 4671
Fax. (+41) (44) 823 4044

Prof. Dr.
Joachim Schoenes(talk)

TU-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

Mr.
Giuseppe Spoto(participant)

University of Turin
Via Pietro Giuria 7
I-10125 Turino

email: giuseppe.spoto@unito.it
Tel. +39 (1) 1670 7832
Fax. +39 (1) 1670 7855

Prof. Dr.
Aldo Steinfeld(talk)ETH Zürich
Dept/Mechanical Engineering
ETH Zentrum ML-J42.1
CH-8092 Zürich

email: aldo.steinfeld@eth.ch
Tel. +41 44 6327929
Fax. +41 44 6321065

Ms.
Doreen Thiele(talk)

EMPA
Hydrogen & Energy
Ueberlandstrasse 129
CH-8600 Dübendorf

email: doreen.thiele@empa.ch
Tel. (+41) (44) 823 4082
Fax. (+41) (44) 823 4022

Dr.
Andras Tompos(talk)

Chemical Research Center
Photocatalysis
Pusztaszeri
HU-1025 Budapest

email: tompos@chemres.hu
Tel. +36 1 4381163
Fax. +36 1 4381143

Mr
Flurin Trepp(participant)SwissRE
Vice president
Mythenquai 50/60
CH-8022 Zürich

email: flurin_trepp@swissre.com
Tel. +41 43 2856571
Fax.

Dr.
Alvaro Valdes de Luxan(talk)

Universiteit Leiden
Leiden Institute of Chemistry
Einsteinweg 55
NL-2300 RA Leiden

email: avdeluxan@chem.leidenuniv.nl
Tel. +31 71 527 4533
Fax. +31 71 527 4397

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Dr.
Roel Van de Krol(talk)

Delft University of Technology
Department DelftChemTech
Julianalaan 136
NL-2628BL Delftemail: R.vandeKrol@tudelft.nl
Tel. +31 15 2782659
Fax.

Dr.
Ronnie Vang
(talk)

University of Aarhus
iNANO (interdisciplinary nanosciencecenter)
Ny Munkegade Build. 1521
DK-8000 Aarhus Cemail: rtv@inano.dk
Tel. +45 8942 5538
Fax.

Dr.
Elli Varkaraki(talk)CRES
RES & Hydrogen Technologies
19th km. Marathonos Av.
GR-19009 Pikermi Attikis

email: evarkara@cres.gr
Tel. +30210 6603397
Fax. +30210 6603301

Dr.
Tejs Vegge(inv. talk)Technical University of Denmark, Risø DTU
Materials Research Department
Frederiksborgvej 399
DK-DK-4000 Roskilde

email: tejs.vegge@risoe.dk
Tel. +45 4677 5818
Fax. +45 4677 5758

Mr.
Björn Wickman(talk)

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

email: bjorn.wickman@chalmers.se
Tel. +46 317725179
Fax. +46 317723134

Prof. Dr.
Adriano Zecchina(inv. lec.)

University of Turin
Sipartimento Chimica IFM
via P. Giuria 7
IT-10125 Torino

email: adriano.zecchina@unito.it
Tel. +39 0116707860
Fax. +39 0116707855

Prof. Dr.
Andreas Züttel
(talk)

Empa
Hydrogen & EnergyÜberlandstrasse 129
CH-8600 Dübendorf

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

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INFORMATIONPROCEEDINGS

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Braunwald is car-free and only reachable by train (funicular railway). The latest departure timein Zürich airport is 20:47 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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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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BRAUNWALDPROCEEDINGS

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