MRM2023/IUMRS-ICA2023

Oral Session | B. Energy | [B-3] Hydrogenomics[B3-O101] Oral 101
Chair: Shin-ichi Orimo (Tohoku Univ.)Mon. Dec 11, 2023 1:30 PM - 3:20 PM Session 1 (Room C-1)

[B3-O101-01 (Symposium Keynote)] Hydrogen the Key Element for the Storage andDistribution of Renewable Energy*Andreas ZÜTTEL1 （1. École Polytechnique Fédérale deLausanne (EPFL) (Switzerland)）
1:30 PM - 2:10 PM[B3-O101-02 (Symposium Keynote)] Catalyst Materials for Efficient Production of
Hydrogen in a Sustainable Economy Driven by
Renewable Energies.
*Juan Ramón Morante1,2 （1. IREC (Spain), 2. The Universityof Barcelona (Spain)）
2:10 PM - 2:50 PM[B3-O101-03 (Symposium Invited)] New Zealand Green-hydrogen technology
platform*John V KENNEDY1,2 （1. GNS Science (New Zealand), 2.
Victoria University of Wellington (New Zealand)）
2:50 PM - 3:20 PM©The Materials Research Society of Japan

B3-O101-01 (Symposium Keynote)

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting

December 11-16, 2023, Kyoto, Japan[Abstract Guideline (Leave two lines for presentation number)]Hydrogen the key element for the storage and distribution of renewableenergyAndreas ZÜTTEL

École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
andreas.zuettel@gmx.ch
Keywords: Hydrogen, Renewable energy, Storage
Countries like Australia have large area with high solar intensity and are, therefore, ideal for harvesting renewableenergy with photovoltaics. The renewable energy can be used to produce hydrogen and products from hydrogenwith nitrogen and carbon. The chemical energy carriers are shipped to the whole world and replace the fossil fuels.
Three parameters are of great importance, the energy density, the conversion efficiency and the final cost of energy
for the future renewable energy economy. On the example of Switzerland and Japan the various storage andtransport options for renewable energy will be elaborated and the cost of the energy estimated.

MRS-Japan© The Materials Research Society of Japan (MRS-J) - B3-O101-01 (Symposium Keynote) -B3-O101-02 (Symposium Keynote)

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting

December 11-16, 2023, Kyoto, Japan[Abstract Guideline (Leave two lines for presentation number)]

Catalyst materials for efficient production of hydrogen in a sustainableeconomy driven by renewable energies.
J. R. Morante

IREC, Catalonia Institute for Energy Research, Plaça de les Dones de Negre,1.
Sant Adrià del Besòs, 08930. Spain.
University of Barcelona, C/Martí i Franquès,1.
Barcelona,08028. Spain.
jrmorante@irec.cat
Keywords: Hydrogen production, Catalyst
A sustainable economy based on renewable energy requires the industrial feasibility of electrochemical
production of hydrogen from renewable energy. This is conditioned by the cost of production, which, on the one
hand, is directly related to the cost of renewable energy and, on the other hand, is related to the productivity andefficiency of the electrolyzer system. In this context, reaching high working current densities in the electrolyzer isa real challenge and exceeding high amperages per cm2 requires the use of catalyst materials with a very highdensity of active sites and with a very high intrinsic activity that must be accompanied by effective configurations
to prevent the blockage of the active sites by the gases produced in the cell.
In this talk, the rational design and use of different catalyst materials for both the anode and the cathode, as
well as their implementation in cells, will be reviewed under the objective of achieving productions based on
current densities greater than several amperes per square centimeter without losing significantly energy efficiency
in production. Likewise, the implications imposed on the design of the electrodes and the cell will also be
considered.
Thus, attention will be paid to the emerging robust and stable electrocatalysts that are more efficient and stableat large current densities in HER and OER, with an outstanding electrocatalytic activity and large stability fromcommercial criteria. Typically, international electrolyzer programs claims for higher current densities than 2A/cm2.

MRS-Japan© The Materials Research Society of Japan (MRS-J) - B3-O101-02 (Symposium Keynote) -B3-O101-03 (Symposium Invited)

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanNew Zealand Green-hydrogen technology platform*

John V Kennedy,

National Isotope Centre, GNS Science, New Zealand, 2 The MacDiarmid Institute for Advanced Materials andNanotechnology, Victoria University of Wellington, New Zealand*j.kennedy@gns.cri.nz
1

Keywords: Hydrogen generation, Electrocatalysis, Hydr
New Zealand’s ambitious goal of presenting a net-zero carbon emissions budget by 2050 depends on
progressively phasing out fossil fuels as an energy source. Recently we started the Green Hydrogen Technology
Platform aimed to deliver transformative technologies that will drive New Zealand’s future as a globallyconnected ‘green-hydrogen’ economy. The Platform’s focus is on technologies that sustainably producehydrogen to replace fossil fuels for electricity generation and transportation, as well as creating smaller-scale
green-hydrogen applications suitable for distributed generation.
Our research themes (Electrocatalysis, Direct photocatalysis and Plasma Catalysis) are focussed on
developing technologies for green hydrogen production that will transform both New Zealand and globalhydrogen production. An overview of our recent research activities will be presented as well as our latest
findings on one-step Fabrication of Earth-Abundant Electrocatalysts for Hydrogen Evolution and Ammonia
Production.

MRS-Japan© The Materials Research Society of Japan (MRS-J) - B3-O101-03 (Symposium Invited) -MRM2023/IUMRS-ICA2023

Oral Session | B. Energy | [B-3] Hydrogenomics[B3-O201] Oral 201
Chair: Hiroyuki Saitoh (National Institutes for Quantum Science and Technology (QST))
Tue. Dec 12, 2023 10:00 AM - 12:00 PM Session 14 (Room J)[B3-O201-01 (Symposium Invited)] Hydrogen embrittlement of metastable
austenitic steels*Motomichi Koyama1, Eiji Akiyama1 （1. Tohoku University(Japan)）
10:00 AM - 10:30 AM[B3-O201-02]

Effect of Oxygen on Plasma Driven Permeationof Hydrogen Through Metal Membranes*Arseniy Kuzmin1, Keisuke Miura1, Shora Kurokawa1, Taiichi
Shikama1, Masahiro Hasuo1 （1. Kyoto University (Japan)）
10:30 AM - 10:50 AM[B3-O201-04]

Fabrication of Zirconium Nitride Hydride
Epitaxial Films by Alternating-Target PulsedLaser Deposition*Daichi Miyazaki1, Ziyang Cao1, Takuto Soma1, Akira Ohtomo1（1. Tokyo Tech. (Japan)）
11:10 AM - 11:30 AM©The Materials Research Society of Japan

B3-O201-01 (Symposium Invited)

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Hydrogen embrittlement of metastable austenitic steels*

M. Koyama1*, Eiji Akiyama1

1

Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aobaku, Sendai, Miyagi, Japan 980-8577
motomichi.koyama.c5@tohoku.ac.jp (Corresponding author)
Keywords: Hydrogen embrittlement, Austenitic steel, Metastable phase, Martensitic transformation*

Hydrogen plays various roles in structural and functional materials. In the case of steels, hydrogen acts as anelement causing embrittlement, i.e., hydrogen embrittlement. The hydrogen embrittlement issue has been regarded
as a bottleneck for developing hydrogen-energy-related infrastructures. In this regard, austenitic steels, which arecomposed of a face-centered cubic (FCC) phase, show significant resistance to hydrogen embrittlement. However,
the austenitic steels can also be susceptible to hydrogen embrittlement when the FCC phase is metastable against
other phases such as hexagonal close-packed (HCP) and body-centered cubic (BCC) phases. More specifically,
when deformation-induced martensitic transformation (diffusionless transformation) occurs during plastic
deformation, hydrogen-related cracking and subsequent premature fracture occur. Because martensitic
transformation is the origin of the high ductility of the austenitic steels, the metastability plays ambivalent roles inmechanical performance in the hydrogen atmosphere. In this talk, we present examples of hydrogen-assisted
cracking and subsequent failure behaviors in metastable austenitic steels toward understanding and controlling thehydrogen-related cracking behavior associated with martensitic transformation.
The first case is the hydrogen embrittlement of a Fe-Mn-based steel that shows deformation-induced FCCHCP martensitic transformation [1]. When the stacking fault energy is low, the austenitic steel shows deformationinduced FCC-HCP martensitic transformation. Hydrogen promotes the FCC-HCP martensitic transformation,
which accelerates HCP-martensite-related crack/void initiation. All of the small cracks/voids were fully arrested
in the remaining austenite regions until the critical strain for restarting damage growth via coalescence of the
micro-damages. Furthermore, lowering the strain rate accelerated the HCP-martensite-related damage growth,which is related to martensite fraction and hydrogen localization [2]. The HCP-martensite-related damage withhydrogen finally results in intergranular and quasi-cleavage fractures.
Another example is a case of FCC-HCP-BCC martensitic transformation in austenitic stainless steels such as
SUS304. Because the BCC martensitic phase is the most susceptible to hydrogen embrittlement, it is generally
known that hydrogen-related cracking occurs at a region where BCC martensite formation preferentially occurs.
In this context, to control the hydrogen-related cracking, the hydrogen-transformation-cracking relationship must
be understood. The BCC martensite-related cracking behavior was clarified by in situ deformation experimentswith scanning electron microscopy. According to our analyses, hydrogen promotes FCC-HCP martensitic
transformation as in the Fe-Mn steel, but the effect of hydrogen on HCP-BCC transformation depends on
deformation temperature. Specifically, hydrogen promotes the formation of BCC martensite at ambient
temperature, however, suppresses at cryogenic temperature. This implies that the hydrogen effect suppressing BCC
martensite formation requires hydrogen diffusion from HCP/BCC phase interface to the BCC martensite region.
To support this interpretation, we will present some experimental results in this talk, in terms of microstructure
distribution and hydrogen desorption during deformation.

References
1) C. Hao, M. Koyama and E. Akiyama. Metallurgical and Materials Transactions A 51, 6184-6192 (2020).
2) C. Hao, M. Koyama, S. Ajito and E. Akiyama. Int. J. Hydrogen Energy 46 (2021) 27221-27233.

MRS-Japan© The Materials Research Society of Japan (MRS-J) - B3-O201-01 (Symposium Invited) -B3-O201-02

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Effect of Oxygen on Plasma Driven Permeation of Hydrogen Through Metal
Membranes*

A. Kuzmin1, K. Miura1, S. Kurokawa1, T. Shikama1, M. Hasuo1

1

Kyoto University, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto 615-8540, Japankuzmin.arseniy.6x@kyoto-u.ac.jp
Keywords: superpermeability, PdCu, hydrogen, plasma-driven permeation, Ni*

Methods for reduction or enhancement of hydrogen penetration in structural materials, specifically metals, aresought after in various technical applications, such as hydrogen energy, fission and fusion projects, and hydrogengeneration. In this work we investigate the effect of oxygen addition in hydrogen plasma on hydrogen transport
through 20 𝜇𝑚 PdCu and 500 𝜇𝑚 Ni membranes.
Normally, oxides ponder the hydrogen transport through metals1). On the other hand, hydrogen permeation
increases if atomic hydrogen is present on the upstream side of a membrane, known as superpermeability, whichstrongly depends on the surface conditions 2).
According to Livshits2), the presence of a contamination
film on the surface of a metal reduces the rate of atomic
hydrogen recombination into molecules, which in turnincreases the permeation. Under plasma exposure thecontamination is removed, and the permeation flux reduces.
Such behavior is especially noticeable for Ni, where thepermeation flux 𝐽 initially raises fast, reaches a maximum, andthen reduces to a steady-state value, as one can see in Fig. 1 b(black line).
In our experiments, we tested this idea by investigating theevolution of the surface oxygen concentration 𝑛𝑂 at different
times after the beginning of plasma exposure. The
experimental setup consists of two vacuum chambers
separated by a membrane, one side of which is exposed toplasma3). A laser breakdown spectroscopy (LIBS) is used toevaluate 𝑛𝑂 from the intensity of OI line (777.1944nm). A
constant oxygen concentration in the fuel mixture 𝑐𝑂2 =15 𝑎𝑡. % is maintained. As one can see from Fig. 1 a, 𝑛𝑂
increases with exposure time. Thus, the previous explanation
Fig. 1. Dynamics of hydrogen plasma driven permeationof such behavior is not satisfactory for the presented result. through Ni at 𝑐𝑂 = 15 𝑎𝑡. %. a – surface concentration of2
Our hypothesis is that instead of being removed, the surface
oxygen, estimated with LIBS, b – time traces of thepermeation flux.
contamination grows and at some the pondering of hydrogen
permeation by the slow diffusion in the oxide becomesstronger than the increase in permeation from the decrease
recombination of hydrogen atoms on the surface.
In Fig. 2 the dependence of 𝐽 on 𝑐𝑂2 is presented for both
metals. Strikingly, one can see the significant increase in 𝐽 for
both cases up to a maximum at 𝑐𝑂2 = 10 − 20 𝑎𝑡. %. Afterthe maximum 𝐽 starts to decrease for both metals. For Ni, thisdecrease is quite severe and 𝑐𝑂2 = 30 𝑎𝑡. % 𝐽 goes below the𝐽(0) for pure hydrogen experiments. For PdCu, however, therate of decrease is quite minimal and 𝐽 remains more than on
Fig. 2. Normalized steady-state hydrogen permeation flux
order of magnitude above 𝐽(0) . This result is especiallythrough PdCu and Ni as a function of oxygen concentration in
important, because it suggests that the supermeability throughfuel mixture.
PdCu could be maintained by creating a thick oxide layer,
which seems to lead only to a minimal degradation of permeation.
References:
1) H. Amundusson, et al., J. Membr. Sci. 153, 259-267 (2000).
2) A. Livshits, et al., J. Nucl. Mater. 170, 79-94 (1990).
3) A. Kuzmin, et al., Fusion Eng. Des. 189, 113462 (2023).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O201-02 -B3-O201-04

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanAbstract Guideline (Leave two lines for presentation number)

Fabrication of Zirconium Nitride Hydride Epitaxial Films by AlternatingTarget Pulsed-Laser Deposition*

D. Miyazaki1, Z. Cao1, T. Soma1, A. Ohtomo1

1

Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan.
miyazaki.d.ad@m.titech.ac.jp
Keywords: Mixed-anion compounds, Metal hydrides, Nitride hydrides, Pulsed-laser deposition, Epitaxy*

Metal nitride hydrides are mixed anion compounds with nitride and hydride ions. This class of mixed anion
compounds exhibits intriguing properties, such as fast hydride conduction in Ba2NH [1] and catalytic activity of
Ca2NH for ammonia synthesis [2]. However, the synthesis of ionic nitride hydrides has been limited to group I andII metals, and as for transition metals, oxyhydrides have been widely explored. Furthermore, the fabrication of
single crystalline films of nitride hydrides remains exceptionally unexplored, perhaps due to hydrogen desorption
at high temperatures, which are favorably applied for epitaxial growth. In this study, we have attained to fabricate
metallic zirconium (Zr) nitride hydride at high temperatures by using pulsed-laser deposition (PLD).
We previously succeeded in PLD of ZrHy (0.7 ≤ y ≤ 3.3) epitaxial films at temperature as high as 600 °C bylaser ablation of a Zr tablet in hydrogen atmospheres. When switched to a ZrN tablet, however, incorporation ofhydrogens into ZrNx films was found to be inactive: y < 0.05 in ZrNxHy. In an alternate approach, we employedalternating-target PLD with taking advantage of strong hydrogen affinity of pure Zr. The Zr nitride hydride films
were fabricated on Al2O3 (0001) substrates at 600 °C in 1×10−3 Torr of H2. The ZrN and Zr tablets were ablated
alternately and the single loop [ZrN/Zr with number of laser pulses in total, N (360 or 180 pulses)] was repeated a
few hundred times to deposit multilayer films with thickness ranging from 200 to 800 nm. X-ray diffraction (XRD)
analysis of the films revealed interesting trends: the peak corresponding to ZrN (111) gradually shifted toward δZrH2 (111) with increasing NZr, and a secondary peak at lower angles was observed for H-rich multilayers [Fig. 1(a)]. The latter indicates the formation of ZrHy (y > 3). The lattice spacings of each reflection are plotted in Fig. 1(b). These findings suggest a mechanism of Zr nitride hydride formation in our method in which interlayerhydrogen (nitrogen) transfer occurs leading to not only homogenous anion distribution [Fig. 1 (c)] but also phaseseparation between N-poor ZrNxHy and ZrHy (y > 3) phases.

Fig. 1. (a) XRD profiles for single and multilayer Zr-based films grown on Al2O3 substrates. (b) Lattice spacing d111 as a function of NZrN.
Filled and open circles indicate ZrNxHy phase and H-rich ZrHy phase, respectively. Broken lines show literature values of bulks. Error bars
indicate full width at half maximum for each peak. (c) Schematic illustration for the formation of ZrNxHy phase.

References
1) F. Altorfer, W. Biihrer, B. Winlder, G. Coddens, R. Essmann, H. Jacobs, Solid State Ionics 70, 272-277(1994).
2) M. Kitano, Y. Inoue, H. Ishikawa, K. Yamagata, T. Nakao, T. Tada, S. Matsuishi, T. Yokoyama, M. Hara, H.
Hosono, Chem. Sci. 7, 4036-4043 (2016).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O201-04 -MRM2023/IUMRS-ICA2023

Oral Session | B. Energy | [B-3] Hydrogenomics[B3-O202] Oral 202
Chair: Shigeyuki Takagi (Tohoku University)
Tue. Dec 12, 2023 2:00 PM - 4:00 PM Session 14 (Room J)[B3-O202-01 (Symposium Keynote)] Improving Hydrogen Storage in Metal-Organic
Frameworks
Linda Zhang1,2, Rafael Balderas-Xicohténcatl1, *Michael
Hirscher1,2 （1. Max Planck Institite for Intelligent Systems(Germany), 2. AIMR, Tohoku Univ. (Japan)）
2:00 PM - 2:40 PM[B3-O202-02]

From Kinetic and Chemical Affinity Sieving and
Beyond: A Metal– Organic Framework for
Hydrogen Isotope Separation*Linda Zhang1,2, Richard Röß-Ohlenroth3, Dirk Volkmer3,
Vanessa K Peterson4, Robert Dinnebier5, Michael Hirscher2（1. Frontier Research Institute for Interdisciplinary Sciences(FRIS), Tohoku University (Japan), 2. Max Planck Institute forIntelligent Systems (Germany), 3. Universität Augsburg(Germany), 4. Australian Nuclear Science and Technology
Organisation (Australia), 5. Max Planck Institute for Solid
State Research (Germany)）
2:40 PM - 3:00 PM[B3-O202-03]

Tubular MIL-68@ZnIn2S4 for Enhanced
Photocatalytic Hydrogen Production
Yu-Hsuan Fan1, *Tai-Chou Lee1 （1. National Central Univ.
(Taiwan)）
3:00 PM - 3:20 PM[B3-O202-04]

Ambipolarity of Dilute Hydrogen in Power
Semiconductor β-Ga2O3 Revealed by μ SR
*Masatoshi Hiraishi1,2, Hirotaka Okabe1,3, Akihiro Koda1,
Ryosuke Kadono1, Takeo Ohsawa4, Naoki Ohashi4, Keisuke
Ide5, Toshio Kamiya5,6, Hideo Hosono6 （1. KEK-IMSS(Japan), 2. Ibaraki Univ. (Japan), 3. Tohoku Univ. IMR (Japan),
4. NIMS (Japan), 5. Tokyo Inst. Tech. (Japan), 6. MCES Tokyo
Inst. Tech. (Japan)）
3:20 PM - 3:40 PM[B3-O202-05]

Local electronic structure of interstitialhydrogen in MgH2 inferred from muon study*Ryosuke Kadono1, Masatoshi Hiraishi2, Hirotaka Okabe3,
Akihiro Koda1,4, Takashi U. Ito5 （1. Inst. Mater. Struct. Sci.,
KEK (Japan), 2. Ibaraki Univ. (Japan), 3. Inst. Mater. Res.,
Tohoku Univ. (Japan), 4. Sokendai (Japan), 5. ASRC, JAEA
(Japan)）3:40 PM - 4:00 PM©The Materials Research Society of JapanMRM2023/IUMRS-ICA2023©The Materials Research Society of Japan

B3-O202-01 (Symposium Keynote)

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Improving Hydrogen Storage in Metal-Organic Frameworks
Linda Zhang1,2, R. Balderas-Xicohténcatl1, *M.Hirscher1,2
1

Max Planck Institute for Intelligent Systems, Stuttgart, Germany, 2 Advanced Institute for Materials Research(WPI-AIMR), Tohoku University, Sendai, Japan*hirscher@is.mpg.de
Keywords: Hydrogen storage, porous materials, adsorption, metal-organic frameworks (MOFs)
Hydrogen storage in nanoporous materials has been attracting a great deal of attention in recent years, as highgravimetric H2 capacities can be achieved at 77 K using materials with particularly high surface areas. Cryogenic
storage by physisorption of hydrogen molecules will safely operate at low pressures, is fully reversible, and has
fast kinetics.
Experimental gravimetric and volumetric hydrogen uptake data have been analysed for many MOFs showing
a linear correlation of the gravimetric absolute uptake with the specific surface area (Chahine’s rule) [1]. Using
the packing density of the powder as well as the single-crystal density, a linear relation is found between thevolumetric absolute hydrogen uptake and the volumetric surface area [2]. The specific total volume occupied bya porous material, i.e. the inverse of its packing or single crystal density, as a function of its specific surface area
yields a linear relationship. Based on these results, a phenomenological model is developed for the volumetricabsolute uptake as a function of the gravimetric absolute uptake, see Fig. 1 [2]. The key to improving thevolumetric storage capacity is closing the gap between the low-density powder towards the theoretical upper
limit of the single crystal by either compaction, pelletizing, or monoliths. Furthermore, interpenetrated
frameworks show generally higher volumetric hydrogen uptakes [3]. Finally, for technical applications, the key
parameter is the usable or working capacity, which is the amount of hydrogen that can be delivered between the
maximum tank pressure and the back pressure required by the end user [4].
The presentation will give an overview of the current status and discuss future concepts [5,6].

Fig. 1. Volumetric vs gravimetric absolute hydrogen uptake of porous materials measured at 77 K and 2.0-2.5 MPa. The volumetricuptake was calculated using packing density (red) and single-crystal density (blue). (Taken from [2])References:1) M. Schlichtenmayer, M. Hirscher, J. Mater. Chem. 22, 10134 (2012).
2) R. Balderas-Xicohténcatl et al., Energy Technol. 6, 578 (2018).
3) R. Balderas-Xicohténcatl et al., Energy Technol. 6, 510 (2018).
4) M. Schlichtenmayer, M. Hirscher, Appl Phys A 122, 379 (2016).
5) D.P. Broom et al., Int. J. Hydrogen Energy 44, 7768 (2019).
6) L. Zhang et al., Progress in Energy 4, 042013 (2022).
MRS-Japan© The Materials Research Society of Japan (MRS-J) - B3-O202-01 (Symposium Keynote) -B3-O202-02

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

From Kinetic and Chemical Affinity Sieving and Beyond: A Metal–Organic
Framework for Hydrogen Isotope Separation*

Linda Zhang1,2, Richard Röß-Ohlenroth3, Dirk Volkmer3, Vanessa K. Peterson4, Robert
Dinnebier5, Michael Hirscher2
1

Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Sendai, Japan, 2 Max Planck
Institute for Intelligent Systems, Stuttgart, Germany, 3 Universität Augsburg, Augsburg, Germany, 4 Australian
Nuclear Science and Technology Organisation, Sydney, Australia, 5 Max Planck Institute for Solid State Research,
Stuttgart, Germany.
*linda.zhang.a3@tohoku.ac.jp
Keywords: Hydrogen energy, Isotope separation, Thermal desorption spectroscopy, Neutron diffraction
Separating H2/D2 mixtures is one of the most challenging issues in modern separation science and technology
since the isotopes have identical size, shape and thermodynamic properties. A promising alternative is the use of
porous materials to separate directly gaseous mixture of isotopes based on two different mechanisms, kinetic
quantum sieving (KQS) [1], here D2 can diffuse faster through small pores than H2, and chemical affinity quantum
sieving (CAQS) [2], where the difference in zero-point energy leads to a stronger adsorption of the heavier isotope.
We investigated various porous materials, e.g., metal-organic frameworks (MOFs) [3-5], covalent organic
frameworks (COFs) [6], and organic porous molecules (POCs) [7] and the best separation factors are around 11 to
13 for KQS below 50 K and for CAQS at 60 to 100 K [8]. At material combining both effects, CAQS and KQS,
showed the highest selectivity of 26 at 77 K so far [9].
Herein, we report a comprehensive
mechanistic study of hydrogenisotope separation in a milestone
MOF compound, metal-azolate
framework M(ta)2, the deuterium
selectivity of which is among thehighest reported as far among all
porous materials. Thermal desorption
spectroscopy (TDS) measurements
indicate this dia type coordination
framework can separate D2 fromanisotope mixture eﬃciently, with a
Fig. 1. D2/H2 separation performance of the M(ta)2 at different temperatures
selectivity of 32.5 at 60 K.
Furthermore, deuterium is enriched to 75% from one cycle from an initial concentration of 5%.,
leading a selectivity over 75. From neutron powder diffraction experiments and accurate data
analysis, we revealed the exact locations of the hydrogen/deuterium molecules in M(ta) 2.
Two adsorption sites of gas molecules have been determined: I) the entrance ofthe pore-surface pockets, which are defined by six ta-ligands arranged alternatively,
and II) the channels connecting adjacent cavities, which are constructed from vertex
sharing tetrahedra. We found that separation of hydrogen isotopes takes place at thechannel sites, in which the D2 interactions are enhanced due to the simultaneously
adsorption. Interestingly, this simultaneously adsorption at site II are exclusive to H2
molecules. Our results also indicate a larger expansion of lattice parameter after H2 loading otherthan its D2 counterpart, leading a favored adsorption of D2 in this framework. Ourfindings shed light on a new mechanism for optimal selectivity for D2 capture from
Fig. 2. Two adsorption sites, with
its isotopic mixture, that rational development of new MOF compounds should focus
site-I and site-II circled out by
on nifty control of expansion.
orange and blue, respectively.

References:[1] J. J. M. Beenakker, et al., Chem. Phys. Lett. 1995, 232, 379. [2] A. FitzGerald, et al., J. Am. Chem. Soc. 2013,
135, 9458. [3] J. Teufel, et al., Adv. Mater. 2013, 25, 635. [4] J. Y. Kim, et al., J. Am. Chem. Soc. 2017, 139,
17743. [5] L. Zhang, et al., J. Am. Chem. Soc. 2019, 141, 19850. [6] H. Oh, et al., Angew. Chem. 2013, 125,
13461. [7] M. Liu, et al., Science, 2019, 366, 613. [8] J. Y. Kim, et al., Adv. Mater. 2019, 31, e1970147. [9] J. Y.
Kim, et al., J. Am. Chem. Soc. 2017, 139, 15135.
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O202-02 -B3-O202-03

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Tubular MIL-68@ZnIn2S4
ProductionforEnhanced

Photocatalytic

HydrogenY.-H. Fan1, *T.-C. Lee1
1

Department of Chemical and Materials Engineering, National Central University, Taoyuan, Taiwan.
taichoulee@ncu.edu.tw
Keywords: Solar Hydrogen, Photocatalyst, Metal-organic-framework*

In recent years, there has been an increasing emphasis on energy-related concerns, specifically regarding
environmental conservation and the limited availability of energy resources. Finding solutions to thesechallenges is of utmost importance for the future. Among the various energy carriers, hydrogen has emerged as awidely recognized clean and versatile source. The production of hydrogen through solar-driven water splitting,known as renewable hydrogen, has gained significant attention. Hence, the development of efficientphotocatalysts for hydrogen energy applications is crucial.
ZnIn2S4 (ZIS) is a transition metal sulfide photocatalyst known for its low cost and visible-light activity,
making it suitable for photocatalytic hydrogen evolution. However, ZIS faces challenges such as low
photocatalytic activity and rapid recombination of photo-generated carriers, resulting in poor efficiency. To
address these issues, this study aimed to modify ZIS using a combination of metal-organic framework (MOF).
By employing a simple oil bath method, a tubular
heterostructure composite was obtained byincorporating indium-based MOF (MIL-68)
particles in the ZIS precursor. MIL-68 possesses atubular structure and higher specific surface areas,
thereby increasing the surface area available forlight absorption and exposing more active sites forthe reaction. Additionally, the heterostructurecomposite (see Fig. 1) effectively facilitate thecharge separation. Excess
To maintain cost-effectiveness, this study did
not employ precious metals such as Pt and Au as
co-catalysts. Various MIL-68/ZIS samples wereprepared, and the hydrogen production was carriedout under 300W Xe lamp with the intensity of 100
Fig. 1: SEM image of the MIL@ZIS composite photocatalyst.
mW/cm2 at room temperature.

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Ambipolarity of Dilute Hydrogen in Power Semiconductor β-Ga2O3 Revealed
by μSR*

Masatoshi Hiraishi1,2, Hirotaka Okabe1,3, Akihiro Koda1, Ryosuke Kadono1, Takeo Ohsawa4,
Naoki Ohashi4, Keisuke Ide6, Toshio Kamiya5,6, and Hideo Hosono6
1

Muon Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research
Organization (KEK-IMSS), Tsukuba, Ibaraki 305-0801, Japan
2
Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan
3
Institute for Materials Research, Tohoku University (IMR), 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
4
National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan
5
Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan
6
Materials Research Center for Element Strategy, Tokyo Institute of Technology (MCES), Yokohama, Kanagawa
226-8503, Japan*masatoshi.hiraishi.pn93@vc.ibaraki.ac.jp
Keywords: β-Ga2O3, Hydrogen, Muon spin rotation

EnergyFormation Energy (eV)Valence band

Gallium oxide β-Ga2O3 has been attracting attention as a semiconductor for high-voltage power devices
because of its large band gap Eg ~4.9 eV. Recent theoretical calculation suggest that interstitial hydrogen can be
the origin of n-type doping [1]. In order to investigate the electronic structure of hydrogen in the dilute limit, wehave performed muon spin rotation/relaxation (μSR) experiments on β-Ga2O3 at the S1 beamline of MLF, J-PARC
to study the electronic structure of muons as pseudo-hydrogen. The local electronic structure of muons is almost
identical to that of hydrogen after a small correction due to the difference in the reduced electron mass (~0.43%),and can be inferred from the hyperfine interaction with the nuclear magnetic moments and/or the electrons.
We demonstrate by μSR study combined with the first principles calculations that muons in β-Ga2O3 have twoelectronic structures: a state corresponding to hydrogen that acts as an electron donor (Mu1), bounded to threecoordinated oxygen, and a hydride-like state in rapid motion (Mu2) [2]. Furthermore, we imply from the Hall effectmeasurements that the fractional yield of Mu2 exhibits a close link with the mobility and density of the carriers(electrons).
The recently established ambipolar model assumes ambipolarity in the sense that muons can take on donor andacceptor states simultaneously as suchmetastablestates(relaxed-excited (a)(b) Mu+
MuBand gap
states) [3]. The present experimental
E+/0 CB
Muresults are in good agreement with this+/0
E0/model, since E
is present in the
E+/0
conduction band, as shown in Fig. 1(a),Mu0
E0/which means that the corresponding H(or Mu) is always ionized [H → H+ + e−,
E+/see Fig. 1(b)] to provide electrons,causing unintended n-type conduction.
Mu+
EFint (charge
Conduction
In addition, while E0/− is located close toneutral level) band
VB
the conduction band, it is on the lower
energy side (left side of the figure) thanthe charge neutral level Eint, suggestingFermi energy (eV)that the state corresponding to E0/− can(a) The relationship between the forma- tion energy of Muq (q = 0,±1) and theactually function as an acceptor andFermi energy in β-Ga2O3 [1], where the symbols E+/0, E0/−, and E+/− correspond to
exchange electrons with the conduction
mutual intersection points among each formation energy of the charged states. (b)band [Mu2 = Mu- ⇄ Mu0 + e-, see Fig.
Schematic diagram of the band structure corresponding to the donor (Mu+ = Mu1)
1(b)] to exhibit fast diffusion motion
and acceptor (Mu− = Mu2) levels.
through the neutral state.
References:
1) H. Li and J. Rovertson, J. Appl. Phys., 115, 203708 (2014).
2) M. Hiraishi, et al., Phys. Rev. B, 132, 105701 (2023).
3) M. Hiraishi, et al., J. Appl. Phys., 132, 105701 (2022).

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Local electronic structure of interstitial hydrogen in MgH2 inferred frommuon study*

R. Kadono1, M. Hiraishi2, H. Okabe3, A. Koda1,4, and T. U. Ito5

1

Muon Science Laboratory, Institute of Materials Structure Science, High Energy Accelerator Research
Organization (KEK-IMSS), Tsukuba, Ibaraki 305-0801, Japan
2
Institute of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, Mito,
Ibaraki 310-8512, Japan
3
Institute for Materials Research (IMR), Tohoku University, Katahira, Sendai 980-8577, Japan
4
Department of Materials Structure Science, The Graduate University for Advanced Studies (Sokendai), Tsukuba,
Ibaraki 305-0801, Japan
5
Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan*ryosuke.kadono@kek.jp
Keywords: hydrogen storage, interstitial hydrogen, electronic structure, muon spin rotation

EnergyXq

Xq

X q (eV)

EnergyX q (eV)

Metal hydrides have attracted attention as one of the
4
(c)
(a)
Mu+i Mu0i Mu-i
candidate materials that can serve as safe and efficient
3(+/0)
Mu0i (para) (0/-)
2hydrogen (H) storages. In particular, MgH2 has great
(+/-)
CBM
1
potential as a solid H-storage material because of its highMu-i (dia)0-1storage capacity of 7.6wt%. However, its slow
Mu+i (dia)VBM-2hydrogenation and dehydrogenation rates and the highEFint-3decomposition temperature (~300°C) are major obstacles-450+(d) [HMu ]i [HMu ]i[HMu ]i(b)to the practical applications. To understand the4[HMu]+i(para) (+/-) [HMu]i(para)3
microscopic mechanisms of the H-related processes, the[HMu]0i(dia)2(0/2-) (0/-)(+/0)(2+/0)
information on the electronic state of interstitial H (which
1[HMu]2i(dia)exists as an intermediate state in the H kinetics) is crucial
0[HMu]2+-1
in gaining insight into the rate-limiting processes. Thei(dia)-2
preceding studies on the microscopic state of H in MgH2
-3
0
1
2
3
4
5
have been mainly via computational approaches based on
EF (eV)density functional theory (DFT), but there have been few(f) Mu0 +e±
(e)
Mu±
i
±
Muthe
experimental investigations to validate the prediction ofFig. 1: The
formation
Elr energyi (X q) of H-related defects vsi
Mu0i +e±
Elr
Fermi
level
(E
)
in
MgH
obtained
byDFT
calculations,
where
F
2
DFT calculations. To overcome this situation, we have
EelV(a) is for the case of interstitial H atoms (Hiq, q = 0,Eel±), and (b)introduced muon (Mu) as pseudo-H into MgH2, andis for the interstitial molecules ([H2]iq, q = 0, ±, 2±),
V>0
V=0
studied their electronic and dynamical properties in detailrespectively corresponding to Mui and [HMu]i. The paraQQ
to elucidate the corresponding interstitial H states.
magnetic states are expressed as ‘para’ and the diamagnetic
states as ‘dia’. The levels for acceptor (E0/-) and donor (E+/0)
As a result, we found four species of Mu states which
are determined as cross points between X +-(EF) and X 0(EF).
are interpreted as two pairs of acceptor-like and donor-like
The dashed line shows the intrinsic charge neutral levelstates predicted by the recently developed “ambipolarity
obtained from the DFT calculation. (Adapted from Ref.[3])model” combined with DFT calculation [1]: in contrast to
Schematic band diagrams for the single electron energy
H whose electronic state is determined by the charge
associated with the donor/acceptor levels (single-charge
conversion levels only) in (a) and (b) are shown in (c) and (d),conversion level (E+/-), that of the paired Mu states can berespectively. The level indicated by a dashed line near the
0/predicted from the positions of acceptor (E ) and donor
CBM in (d) is a shallow state suggested from DFT calculations.
(E+/0) levels in the band structure [2]. A majority pair is
identified as Mui- and Mui+/0 corresponding to the interstitial H (Hi), and another pair is [HMu]i0 and [HMu]i+ for
the interstitial molecules ([H2]i), respectively (see Fig. 1). These findings provide an indirect support for the DFT
calculations on which the model is based via the donor/acceptor levels [3].
An important implication of the muon results is that the improvement in hydrogen kinetics, such as by ball
milling with oxidants, is due to dehydrogenation acting as a ‘reduction’ for hydrides and stabilizing the interstitial
H- state [1]. As can be seen in Fig. 1(a), when EF is pushed up above EFint by dehydrogenation, the interstitial H
becomes stable in the Hi- state, and H can exhibit interstitial diffusion without binding to the ligand H-.
References:
1) R. Kadono, M. Hiraishi, H. Okabe, A. Koda, and T. U. Ito, J. Phys.: Condens. Matt. 35, 285503 (2023).
2) M. Hiraishi, H. Okabe, A. Koda, R. Kadono, and H. Hosono, J. Appl. Phys. 132, 105701 (2022).
3) A. Roy, A. Janotti, and C. G. Van de Walle, Appl. Phys. Lett. 102, 033902 (2013).

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Oral Session | B. Energy | [B-3] Hydrogenomics[B3-O203] Oral 203
Chair: Hiroyuki Saitoh (National Institutes for Quantum Science and Technology (QST))
Tue. Dec 12, 2023 4:30 PM - 6:30 PM Session 14 (Room J)[B3-O203-01] Hydrogen Storage Properties and Crystal Structures of an AB3 basedalloy*Toyoto Sato1, Kazuki Obana1, Denis Sheptyakov2, Takashi Honda3,4, Hajime Sagayama4,
Kouji Sakaki5, Shigeyuki Takagi6, Tatsuoki Kono6, Heena Yang7,8, Wen Luo7,8, Loris
Lombardo7,8, Andreas Züttel7,8, Shin-ichi Orimo6,9 （1. Shibaura Institute of Technology(Japan), 2. Paul Scherrer Institut (Switzerland), 3. J-PARC Center, High Energy Accelerator
Research Organization (KEK) (Japan), 4. Institute of Materials Structure Science, HighEnergy Accelerator Research Organization (KEK) (Japan), 5. National Institute of Advanced
Industrial Science and Technology (Japan), 6. Institute for Materials Research, Tohoku
University (Japan), 7. Institute of Chemical Sciences and Engineering, Basic Science
Faculty, École Polytechnique Fédérale de Lausanne (EPFL) Valais/Wallis (Switzerland), 8.
Empa Materials Science and Technology (Switzerland), 9. Advanced Institute for Materials
Research (WPI-AIMR), Tohoku University (Japan)）
4:30 PM - 4:50 PM[B3-O203-02] Formation Gap in Transition Metal Hydrides*Hiroshi MIZOGUCHI1, S.-W. PARK1,2, Hideo HOSONO1,2 （1. National Institute forMaterials Science (Japan), 2. Tokyo Institute of Technology (Japan)）
4:50 PM - 5:10 PM[B3-O203-03] How to evaluate hydrogen storage properties by van’ t Hoff plots
and Sieverts’ method in the pressure range up to 100 MPa*Véronique Charbonnier1, Kohta Asano1, Hyunjeong Kim1, Kouji Sakaki1 （1. National Inst.
of Advanced Indus. Sci. and Tech. (AIST) (Japan)）
5:10 PM - 5:30 PM[B3-O203-04] Nitrogen Dissociation and Ammonia Synthesis Properties of Lithium
based Compounds*Hiroki Miyaoka1, Hitoshi Saima1, Takayuki Ichikawa1 （1. Hiroshima Univ. (Japan)）
5:30 PM - 5:50 PM[B3-O203-05] Complex hydrides for carbon capture and conversion*Loris Lombardo1, Andreas Züttel2, Satoshi Horike1 （1. Kyoto Univ. (Japan), 2. EPFL
(Switzerland)）
5:50 PM - 6:10 PM©The Materials Research Society of Japan

B3-O203-01

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Hydrogen Storage Properties and Crystal Structures of an AB3 based alloy*

T. Sato1, K. Obana1, D. Sheptyakov,2 T. Honda,3, 4 H. Sagayama,4 K. Sakaki,5 S. Takagi,6T. Kono,6 H. Yang,7, 8 W. Luo,7, 8 L. Lombardo,7, 8 A. Züttel,7, 8 S. Orimo,6, 9

Shibaura Institute of Technology, Japan, 2 Paul Scherrer Institut, Switzerland, 3 J-PARC Center, High Energy
Accelerator Research Organization (KEK), Japan, 4 Institute of Materials Structure Science, High Energy
Accelerator Research Organization (KEK), Japan, 5 National Institute of Advanced Industrial Science andTechnology, Japan, 6 Institute for Materials Research, Tohoku University, Japan, 7 Institute of Chemical Sciencesand Engineering, Basic Science Faculty, École Polytechnique Fédérale de Lausanne (EPFL) Valais/Wallis,
Switzerland, 8 Empa Materials Science and Technology, Switzerland. 9 Advanced Institute for Materials Research(WPI-AIMR), Tohoku University, Japan.
*
toyoto@shibaura-it.ac.jp
Keywords: Hydrogen Storage, Crystal structure, Neutron and X-ray diffraction
1

Hydrogen storage materials have higher volumetric hydrogen densities, which indicate compact hydrogenstorage methods, than gaseous and liquid hydrogen. For the reason, many hydrogen storage materials have beenreported. Typical hydrogen storage materials, which refer to ABx alloys (typically x = 1-5) composed of A and B
metal elements (A: elements in Group 1-5; B: elements in Group 6-12), store hydrogen atoms in interstitial sites
in their lattices. Although LaNi5 based alloys (so-called AB5 alloys) have been presently used as practicalhydrogen storage materials, new materials with higher hydrogen storage capacity have been demanded.
Recently, we reported reversible hydrogen absorption and desorption reactions on AB2 based alloys, whichwere (Y, Mg)(Co, Ni)2 synthesized from YCo2 and MgNi2. In the results, their equilibrium hydrogen pressuresand hydrogen storage capacities were depended on amounts of Mg and Co.1,2 On the other hand, using YCo2 andMgCo2 as starting materials, AB3 based alloys (Y, Mg)Co3 were formed instead of AB2 based alloys.
Interestingly, (Y, Mg)Co3 exhibited reversible hydrogen absorption and desorption reactions at 303 K with lessequilibrium hydrogen pressure differences between the hydrogen absorption and desorption reactions (so-called
less hysteresis) as shown in Figure 1. In addition, the equilibrium hydrogen pressures and hydrogen storage
capacities were maintained up to 100 cycles. To understand the reactions viewed from atomic arrangements, weobserved crystal structures by neutron diffraction under D2 pressure. Based on the Rietveld refinements on theneutron diffraction data combined with synchrotron radiation X-ray diffraction data, the experimentally observed
neutron diffraction patterns before and after deuterium absorption reactions were reasonably reproduced byrhombohedral crystal structure models (a = 4.99719(67) Å and c = 24.16062(533) Å before D2 absorption
reaction, and a = 5.27370(64) Å and c = 25.68827(553) Å after D2 absorption reaction).
In our presentation at MRM2023/IUMRS-ICA2023
Grand Meeting, we will present details of syntheses,
hydrogen storage properties and crystal structures of(Y, Mg)Co3.
This research was supported by JST SICORP(JPMJSC 1802), MEXT/JSPS KAKENHI (JP18H05513
and JP18H05518 (“Hydrogenomics”), 19K05051,
22H01817), and the GIMRT Program of the Institute forMaterials Research, Tohoku University (Proposal No.
202106-RDKGE-0102).
Neutron diffraction experiments were performed on
the HRPT at the SINQ, PSI, Switzerland (Proposal No.:
20202035). Synchrotron powder X-ray diffraction were
performed on the BL-8A at the PF, KEK, Japan(Proposal No. 2019G572).

Fig. 1 Hydrogen absorption and desorption reactions of(Y, Mg)Co3 at 303 K
Black and red indicate on the 3rd and 100th cycles,
respectively. Open and closed circles indicate absorption
and desorption, respectively

References:
1) T. Sato, K. Ikeda, T. Honda, L. L. Daemen, Y. Cheng, T. Otomo, H. Sagayama, A. J. Ramirez-Cuesta, S.
Takagi, T. Kono, H. Yang, W. Luo, L. Lombardo, A. Züttel, S. Orimo, J. Phys. Chem. C 126, 16943-16951(2022).
2) T. Sato, T. Mochizuki, K. Ikeda, T. Honda, T. Otomo, H. Sagayama, H. Yang, W. Luo, L. Lombardo, A.
Züttel, S. Takagi, T. Kono, S. Orimo, ACS Omega 5, 31192-31198 (2020).

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanAbstract Guideline (Leave two lines for presentation number)

Formation Gap in Transition Metal Hydrides*

Hiroshi Mizoguchi1, Sang-Won Park1, 2, 3, Hideo Hosono1, 2

1Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS) ,Tsukuba, Ibaraki 305-0044, Japan, 2 MDX Research Center for Element Strategy, International Research
Frontiers Initiative, Tokyo Institute of Technology, Midori-ku, Yokohama 226- 8503, Japan, 3 Present address:
Department of Chemical and Materials Engineering, University of Suwon, Hwaseong, Gyeonggi 18323,
Republic of Korea*
mizoguchi.hiroshi@nims.go.jp
Keywords: Hydrogen, intermetallics, chemical bond, electronic structure
In hydrogen society, metal hydrides which are carriers of hydrogen will play crucial role in the applicationsuch as hydrogen storage, fuel cell, catalytic reactions, and hydrogen penetration.1) Fig. 1(a）shows theclassification of binary hydrides in the view point of chemical bonding character. We can see four regions in the
periodic table. Interestingly, there is a no formation region around late transition metals (LTMs), which is called
as “hydride gap”. Besides, we notice unsolved problems related to the gap. For example, (a)Pd locates in theregion exceptionally, although it has strong affinity with hydrogen. (b) The incorporation of a small amount(10−20 mol %) of electropositive metal into an LTM collapses the gap region, and the hydrogen (H) storage
ability improves markedly, as seen in H storage intermetallics (IMs) such as LaNi5. We analyzed the chemicalbonding between LTMs and H over various IMs.
We first clarified the characteristic chemical bonding in Pd hydride (PdH), using DFT calculations, andsubsequently, found strong covalent interaction of Pd 4d-H 1s. This is due to close energy levels of these orbitals.
And it is consistent with large workfunction of Pd (~5.1 eV)2). We found the unique property of Pd originatesfrom its lattice softness.3) Fig. 1(b) shows the bulk modulus values of elements. We easily found the thresholdvalue (~180 GPa) of hydride formation. Although Cu, Ag, and Au have B values smaller than 180 GPa, these
metals do not form hydrides owing to the fully occupied d 10 state. Besides, most of the known H storage IMs
including LaNi5 also meets the above criterion (Fig. 1(b)). Indeed, negatively charged LTM ions, such as Niδ− in
LaNi5, play a crucial role in hydrogenation. These ions cause lattice softening, which renders H solution possible.
The criterion proposed seems to provide a guide to design new H storage materials. We are currently verifying
its effectiveness by applying to various IMs.

Fig. 1(a) Formation map of metal hydrides. Late transition metals (LTMs) cannot form hydrides, while most elements can form stable
hydrides. An exception is Pd locating around the center of LTMs in the periodic table. (b) Bulk modulus values of transition metals andseveral H storage intermetallic compounds. The elements with H storage ability are written as blue text. Transition metals are hard generally,
because of the contribution of d electrons into chemical bonding. One can easily found the threshold value (~180 GPa) of hydride formation.

References :1) R. Mohtadi, S. Orimo, Nat. Rev. Mater. 2, 16091/1−15 (2017)2) H. B. Michaelson, J. Appl. Phys. 48, 4729−4733 (1977)
3) H. Mizoguchi, S.-W. Park, H. Hosono, J. Am. Chem. Soc. 143, 11345-11348 (2021)
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O203-02 -B3-O203-03

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

How to evaluate hydrogen storage properties by van’t Hoff plots andSieverts’ method in the pressure range up to 100 MPa*

V. Charbonnier, K. Asano, H. Kim, *K. Sakaki

National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan*v.charbonnier@aist.go.jp and kouji.sakaki@aist.go.jp
Keywords: high hydrogen pressure, metal hydride, Sieverts’ method, van’t Hoff plot
Recently, interest in metal hydride forming compounds with high sorption pressures for compressor
applications has raised. This enthusiasm can be explained by the possibility to run compression on waste heatrather than electricity, giving the possibility to lower energy consumption. But together with the exploration of
the as yet little studied high-pressure regions, new problems to be tackled have emerged.
Calculation of van’t Hoff plots at high pressure
In this field, a simplified van’t Hoff
equation that links the pressure to the inverse
temperature is often used to predict sorption
pressures (red in Fig. 1). For research in highpressure applications, it becomes especially
useful because in most laboratories, ahydrogen pressure higher than 10 MPa isdifficult to achieve. In this talk, we will explainthat this equation is true at low pressures, butthat its use for extrapolation in thehigh-pressure range leads to overestimation of
the sorption pressures.
P-c isotherms of an AB2 compound havebeen measured in a wide range of pressure andtemperatures. The data points in Fig. 1 show
the middle of their sorption plateaus(■ absorption, □ desorption). The pink data
points are derived from low pressure andtemperature measurements. These pink data
points were used to calculate Van’t Hoff plots
shown in Fig. 1 with two methods (red andgreen lines). The red van’t Hoff plots are linear Figure 1: Comparison of van't Hoff plots considering fugacity (green) and notfits, i.e. the van’t Hoff plots derived from the considering fugacity (red). The symbols are the experimental data
simplified equation described above. The green corresponding to the middle of the plateaus of the P-c isotherms forabsorption ■ and desorption □ of an AB2 Laves phase compound. Only the
van’t Hoff plots, considering the fugacity, f, pink data points were used to draw the van’t
Hoff plots.
clearly shows better agreement with the blue
high pressure data points. Showing that the fugacity should be considered instead of pressure in thehigh-pressure range. Here, we will explain how to use the fugacity to solve this issue [1], and hereby calculate
correct and curved van’t Hoff plots (green).
High-pressure equipment related issues
The investigation of high pressure is full of surprises and here we will also introduce unexpected issues that
we faced and solved when setting up our high-pressure apparatus (up to 100 MPa). These issues are related tothe inner volume of the valve that separates the sample holder from the PCT apparatus, the pressure incrementthat results from the closure of this valve and the change in sample volume induced by sorption of hydrogen by
the samples [2].

References:[1] V. Charbonnier, H. Enoki, K. Asano, H. Kim, K. Sakaki, Int J Hydrogen Energy 46, 36369-80 (2021).
[2] V. Charbonnier, K. Asano, H. Kim, K. Sakaki, J. Alloys Compd. under review.
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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Nitrogen Dissociation and Ammonia Synthesis Properties of Lithium based
Compounds*

Hiroki Miyaoka1, Hitoshi Saima1, Takayuki Ichikawa1,2

1Natural Science Center for Basic Research and Development, Hiroshima University, 739-8530, Japan,
Graduate School of Advanced Science and Engineering, Hiroshima University, 739- 8527, Japan*miyaoka@hiroshima-u.ac.jp
Keywords: Ammonia, Lithium, Chemical looping, Hydride, Alloy
2

Ammonia (NH3) is recently recognized as an attractive energy or hydrogen carrier to effectively store andtransport renewable energy because of the high gravimetric and volumetric energy density. For the NH3
production from unstable renewable energy, research and development of the effective small-scale NH3 synthesis
processes operated under lower pressure than those of the conventional mass production system are required.
The chemical looping process composed of several chemical reaction are potential techniques to establish theabove small-scale NH3 production system.
In this work, the NH3 synthesis processes by chemical looping using Lithium (Li) based compounds, whichare Li-14 group element (M = Si, Ge, Sn. Pb) alloys and LiH, are studied1-4). The nitrogen (N2) dissociation
properties of the Li compounds were systematically investigated by the reaction with 0.1 MPa of N2 gas andcompared with the chemical state of Li in the compounds, which is characterized by nuclear magnetic resonance(NMR) analysis. The correlation between the N2 dissociation temperature and metallic feature of Li wasclarified4), namely the more metallic Li can interact with N2 molecules at lower temperature. In the case of LiH,
the N2 dissociation temperature is the highest because Li is ionic state (Li+).
The NH3 synthesis by chemical looping of LiH is composed of following two step exothermic reactions
operated under 0.1 MPa of N2 and H23,5).
4LiH + N2→ 2Li2NH + H2
2Li2NH + 4H2→ 2NH3 + 4LiH
The improvement of reaction kinetics is issue for the NH3 synthesis by LiH since the melting and agglomerationof intermediate phase occurred during the reaction with N2. By mixing scaffolds such as Li2O and BN to preventthe agglomeration, the reaction kinetics is drastically improved, and the reaction yield is reached to be almost
100% within 20 min3). To realize effective NH3 synthesis, suitable reaction processes including heat management
should be designed considering the unstable H2 supply from renewable energy in future works.
The chemical looping process of the Li-M alloys is composed of following three step reactions, which are N2
dissociation to form Li3N, NH3 synthesis by reaction between Li3N and H2, and regeneration of initial alloys
from LiH4).
Li4.4M + (x/2)N2→ xLi3N + Li4.4-3xM
xLi3N + 3xH2
→ xNH3 + 3xLiH
Li4.4-3xM + 3xLiH → Li4.4M + (3x/2)H2
For all the alloys, NH3 can be synthesized below 500 °C under 0.1 MPa by a gas-switching process(N2→H2→Ar). Although the synthesis processes are complicated compared with that of LiH, high durability canbe expected due to the characteristic atom dynamics based on the high diffusivity of Li2).
This work is supported Grant-in-Aid for Scientific Research (B), JP20H02465 subsidized by JSPS and a
project, JPNP2004, subsidized by the New Energy and Industrial Technology Development Organization(NEDO). We would like to thank Research Center for Nitrogen Recycling Energy Carrier at Hiroshima
University.
References:
1) T. Yamaguchi, K. Shinzato, K. Yamamoto, Y. Wang, Y. Nakagawa, S. Isobe, T. Ichikawa, H. Miyaoka, and T.
Ichikawa, Int. J. Hydrogen Energy, 45, 6806–6812 (2020).
2) S. Yamaguchi, T. Ichikawa, Y. Wang, Y. Nakagawa, S. Isobe, Y. Kojima, and H. Miyaoka, ACS Omega, 2,1081–1088 (2017).
3) K. Tagawa, H. Gi, K. Shinzato, H. Miyaoka, and T. Ichikawa, J. Phys. Chem. C, 126, 2403–2409 (2022).
4) K. Shinzato, K. Tagawa, K. Tsunematsu, H. Gi, P. K. Singh, T. Ichikawa, and H. Miyaoka, ACS Appl.
Energy Mater., 5, 4765–4773(2022).
5) W. Gao, J. Guo, P. Wang, Q. Wang, F. Chang, Q. Pei, W. Zhang, L. Liu, P. Chen, Nat. Energy, 3, 1067–1075(2018).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O203-04 -B3-O203-05

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Complex hydrides for carbon capture and conversion*

L. Lombardo1, A. Züttel2, S. Horike1 (12-point)

1

Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan; 2 LMER, EPFL, Sion,
Switzerland.
*
lombardo.loris.75a@st.kyoto-u.ac.jp
Keywords: Borohydride, Ammonia Borane, Carbon Dioxide
Carbon dioxide (CO2) emission is responsible for global warming but also represents a cheap, abundant, andsafe carbon source. During the last few years, CO2 capture and utilization have been a global-intensive researcharea. Conversion of CO2 to chemicals or synthetic fuels is a promising method to valorise this greenhouse gas
and tackle climate change. However, due to CO2 stability, expensive catalysts or harsh conditions are often
required.

By using ammonia borane (AB) instead ofborohydrides, new valuable products can be obtained.
We demonstrate the catalyst- and solvent-free
reduction of CO2 with AB by carefully controlling thereaction pressure and temperature (Fig. 1). The
kinetics, thermodynamics, and mechanism werestudied by microbalance, FT-IR, and NMR. Under
optimal conditions, up to 38 mmol of CO2 was
reduced per gram of AB (1.68 gCO2 · g-1AB).
Formamide was identified as the main product,
indicating a transfer of formate from the boron to thenitrogen. Adding a secondary amine to the ABprovides the N-formylation product in 48% yield.
Finally, N-doped carbon was obtained by calcinating
the reaction product between AB and CO2, which
represents a new method for the synthesis offunctionalized carbon materials from CO2.

(a)
T, P

+

(b)

(c)
40

CO2 absorbed (mmol × g-1)

Here we demonstrate how to use complex hydrides,
well-known materials for solid-state hydrogen storage,
for CO2 capture and reduction.[1] Organic
borohydrides reactivity allows the capture andreduction of CO2 from dilute sources and even fromthe atmosphere, formate being the main reaction
product.[2,3] The increase in reactivity comes from thecharge transfer between the ammonium cation andborohydride anion.

0.8 MPa CO2, 16h

35

T < 70 ℃

30
25
20
15
10

T > 70 ℃

5
0
40

45

50

55

60

65

70

Temperature (C)

Fig. 1: (a) Schematic representation of the reaction
between ammonia-borane and CO2; (b) the amount of
CO2 absorbed in function of temperature: (c) sample
appearance after reaction with CO2.

These findings can promote the use of complex
hydrides for the valorisation of CO2 to chemicals andmaterials under mild conditions.

References[1]
L. Lombardo, H. Yang, S. Horike, A. Züttel, MRS Bull. 2022, 47, 424–431.
[2]
L. Lombardo, H. Yang, K. Zhao, P. J. Dyson, A. Züttel, ChemSusChem 2020, 13, 2025–2031.
[3]
L. Lombardo, Y. Ko, K. Zhao, H. Yang, A. Züttel, Angew. Chem. Int. Ed. 2021, 60, 9580–9589.

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O203-05 -MRM2023/IUMRS-ICA2023

Poster Session | B. Energy | [B-3] Hydrogenomics[B3-P204] Poster 204
Tue. Dec 12, 2023 6:30 PM - 8:30 PM Poster (Annex)[B3-P204-01] The effective treatment of hydrogen boride (HB) sheets for the longterm stabilization as the hydrogen storage*Shin-ichi Ito1, Miwa Hikichi1, Natsumi Noguchi1, Mei Yuan1, Zihao Kang1, Kosei Fukuda1,
Masahiro Miyauchi2, Iwao Matsuda3, Takahiro Kondo1,4 （1. Univ. of Tsukuba (Japan), 2.
Tokyo Inst. of Tech. (Japan), 3. The Univ. of Tokyo (Japan), 4. Tohoku Univ. (Japan)）[B3-P204-02] Effects of High-temperature Heating of Hydrogen Boride Sheets
Under High-Hydrogen Partial Pressure*Yukihiro Yasuda1, Kazuho Goto2, Yuki Nakahara3, Reina Utsumi4, Hiroyuki Saitoh5, Satoshi
Nakano6, Shin-ichi Ito7, Miwa Hikichi8, Shin-ichi Orimo9, Takahiro Kondo10 （1. Univ.
Tsukuba (Japan), 2. Univ. Tsukuba (Japan), 3. QST (Japan), 4. QST (Japan), 5. QST (Japan),
6. NIMS (Japan), 7. Univ. Tsukuba (Japan), 8. Univ. Tsukuba (Japan), 9. Tohoku Univ.
(Japan), 10. Univ. Tsukuba (Japan)）[B3-P204-03] Controlling Ultraviolet Photo-Induced H2 Release Rate by Tuning B-H
Bonds in Free-Standing Borophane*Miwa Hikichi1, Junpei Takeshita2, Natsumi Noguchi1, Shin-ichi Ito1, Luong Thi Ta3,4, Kurt
Irvin M. Rojas3, Iwao Matsuda5, Satoshi Tominaka6,7, Yoshitada Morikawa3, Ikutaro Hamada
3, Masahiro Miyauchi2, Takahiro Kondo1,8 （1. Univ. Tsukuba (Japan), 2. Tokyo Tech.

(Japan), 3. Osaka Univ. (Japan), 4. Vietnam Maritime Univ. (Viet Nam), 5. Univ. Tokyo(Japan), 6. CBRM (Japan), 7. NIMS (Japan), 8. Tohoku Univ. (Japan)）[B3-P204-04] Evaluation of NH3 adsorption properties on hydrogen bolide sheets*Kosei Fukuda1, Shin-ichi Ito2, Miwa Hikchi2, Iwao Matsuda3, Takahiro Kondo2,4 （1.
Graduated school of Pure and Applied Sciences, Tsukuba Univ. (Japan), 2. Department ofMaterials Science and Tsukuba Research Center for Energy Materials Science, Institute ofPure and Applied Sciences, Tsukuba Univ. (Japan), 3. Institute for Solid State Physics,
Tokyo Univ. (Japan), 4. The Advanced Institute for Materials Research, Tohoku Univ.
(Japan)）[B3-P204-05] Investigation on the Catalytic Performance of Hydrogen Boride for theConversion of Ethanol and Ethanol Solution*Zihao Kang1, Shin-ichi Ito2, Miwa Hikichi2, Takahiro Kondo2,3 （1. Graduate School ofPure and Applied Sciences, Univ. Tsukuba (Japan), 2. Department of Materials Science andTsukuba Research Center for Energy Materials Science, Institute of Pure and Applied
Sciences, Univ. Tsukuba (Japan), 3. Advanced Institute for Materials Research (WPI-AIMR),
Univ. Tohoku (Japan)）[B3-P204-06] Electronic and optical properties of the hydrogen boride sheet fromthe many-body perturbation theory*Luong Thi Ta1, Yoshitada Morikawa1, Ikutaro Hamada1 （1. Osaka Univ. (Japan)）[B3-P204-07] Interplay of Hydrogen Boride Sheets with Water: Insights into Surface
and Edge Stability*Kurt Irvin Medina Rojas1, Yoshitada Morikawa1,2, Ikutaro Hamada1 （1. Department ofPrecision Engineering, Graduate School of Engineering, Osaka University (Japan), 2.
Research Center for Precision Engineering, Graduate School of Engineering, Osaka©The Materials Research Society of JapanMRM2023/IUMRS-ICA2023

University (Japan)）[B3-P204-08] Investigation of carrier properties of rhombohedral boron
monosulfide and changes in properties due to impurity doping*Norinobu Watanabe1, Keisuke Miyazaki2, Masayuki Toyoda2, Koutarou Takeyasu1, Naohito
Tsujii3, Haruki Kusaka1, Akiyasu Yamamoto4, Susumu Saito2, Masashi Miyakawa3, Takashi
Taniguchi3, Takashi Aizawa3, Takao Mori3, Masahiro Miyauchi2, Takahiro Kondo1,5 （1.
Univ. Tsukuba (Japan), 2. Tokyo Tech. (Japan), 3. NIMS (Japan), 4. TAT (Japan), 5. WPIAIMR, Tohoku Univ. (Japan)）[B3-P204-09] Edge dominated Hydrogen Evolution Reactions in Ultra narrow MoS2
Nanoribbon Arrays*Ding-Rui Chen1,2,3, Hao-Ting Chin1,2,3, Mario Hofmann4, Ya-Ping Hsieh1,2,3 （1.
International Graduate Program of Molecular Science and Technology,National Taiwan
Univ. (Taiwan), 2. Inst. of Atomic and Molecular Sciences, Academia Sinica (Taiwan), 3.
Molecular Science and Technology Program, Taiwan International Graduate Program,
Academia Sinica (Taiwan), 4. Department of Physics, National Taiwan Univ. (Taiwan)）[B3-P204-10] Diffusion-restricted Cation Exchange Synthesis Of Ultrafine Rh
Electrocatalyst For Hydrazine Assisted Hydrogen Production*Hak Hyeon Lee1, Ji Hoon Choi1 （1. Sungkyunkwan Univ. (Korea)）[B3-P204-11] Photocatalytic Hydrogen Production from Na2S/Na2SO3 Solution with
Visible Light Responsible g-C3N4/(CuAg)0.1In0.2Zn1.6S2*Satoshi Asakuma1, Mai Furukawa1, Ikki Tateishi1, Hideyuki Katsumata1, Satoshi Kaneco1（1. Mie Univ. (Japan)）[B3-P204-12] Construction of highly active photocatalytic system using edgegrafted g-C3N4*Mayu Yoshimura1, Hideyuki Katsumata1, Ikki Tateishi1, Mai Furukawa1, Satoshi Kaneco1（1. Mie Univ. (Japan)）[B3-P204-13] Study on LaFeO3 photocathode for long-term stable
photoelectrochemical water splitting*Hyunwoong Seo1, Kyumi Han1, Min-Kyu Son2 （1. Inje Univ. (Korea), 2. Korea Inst. of
Ceramic (Korea)）[B3-P204-14] Electrodeposited Cu2O with a reduced interfacial amorphous phaseusing artificially oriented ITO and their enhanced
photoelectrochemical solar to H2 efficiency*Ji Hoon Choi1, Hak Hyeon Lee1, Hyung Koun Cho1 （1. Sungkyunkwan Univ. (Korea)）[B3-P204-15] Simulation of Water Electrolysis of Polymer Electrolyte Membranes
Kentaro Haraguchi1, Ryo Mitsui2, *Hidekazu Yokomakura3 （1. Toyota TechnicalDevelopment Corp. (Japan), 2. Toyota Technical Development Corp. (Japan), 3. Toyota
Technical Development Corp. (Japan)）[B3-P204-16] Eco-friendly Electrochemical Ammonia Oxidation of NiCuP
Electrocatalyst for Hydrogen production*Chanmin Jo1, Subramani Surendran1,Pildo Jung2, Dongjin Lee2, Il Goo Kim2,Uk Sim1,2 （1.
Korea Inst. of Energy Tech. (Korea), 2. NEEL Sci., INC. (Korea)）[B3-P204-17] Membrane Reactor Combining V-based Hydrogen Permeable Alloy
Membrane with Ammonia Decomposition Catalyst for Direct HighPurity Hydrogen Production from Ammonia©The Materials Research Society of JapanMRM2023/IUMRS-ICA2023*Kaori Omata1, Katsutoshi Sato2, Katsutoshi Nagaoka2, Hiroshi Yukawa2, Yoshihisa
Matsumoto3, Tomonori Nambu4 （1. Univ. of Yamanashi (Japan), 2. Nagoya Univ. (Japan),
3. National Inst. of Tech., Oita College (Japan), 4. National Inst. of Tech., Suzuka College(Japan)）[B3-P204-18] The effect of ball milling on hydrogen release property of TiH2
*Mei Yuan1, takahiro Kondo1,2 （1. Tsukuba Univ. (Japan), 2. Tohoku Univ. (Japan)）[B3-P204-19] Hydrogen-gasochromic Properties of Y-Mg, Ni-Mg, Mn-Mg and Gd
Switchable Mirror Films*Jiaxin Wang1, Tomoya Matsuno1, Makoto Kashiwagi1, Iesari Fabio2, Toshihiro Okajima1,2,
Yuki Oguchi1,3, Yuzo Shigesato1 （1. Aoyama Gakuin University (Japan), 2. Aichi
Synchrotron Radiation Center (Japan), 3. Center for Instrumental Analysis (Japan)）[B3-P204-20] Fabrication of all-solid-state thin film thermal switches using hydro/dehydrogenation reactions of Y-Mg or Ni-Mg switching-mirror films*Haruna Ogiwara1, Ryuto Nishimura1, Makoto Kashiwagi1, Yuki Oguchi1, Yuichiro
Yamashita2,1, Takashi Yagi2,1, Naoyuki Taketoshi2,1, Yuzo Shigesato1 （1. Aoyama Gakuin
Univ. (Japan), 2. National Inst. of Advanced Indus. Sci. and Tech. (Japan)）[B3-P204-21] Thermal conductivity changes of electrochemically hydrogenated anddehydrogenated Pd-catalyzed Ni-Mg alloy thin film
*Daiki Murakami1, Yuichiro Yamashita2,1, Takashi Yagi2,1, Makoto Kashiwagi1, Yuki Oguchi1, Naoyuki Taketoshi2,1, Yuzo Shigesato1 （1. Aoyama Gakuin Univ. (Japan), 2. National
Institute of Advanced Industrial Science and Technology (Japan)）[B3-P204-22] Reversible electrical and thermal conductivities change of Pdcatalyzed Co-Mg films by gasochromic hydrogenation using N2-H2(3%) gas*Koki Nakano1, Yuichiro Yamashita2,1, Takashi Yagi2,1, Makoto Kashiwagi1, Yuki Oguchi1,
Iesari Fabio3, Toshihiro Okajima3,1, Naoyuki Taketoshi2,1, Yuzo shigesato1 （1. Aoyama
Gakuin Univ (Japan), 2. National Inst of Advanced Indus Sci and Tech (Japan), 3. Aichi
Synchrotron Radiation Center (Japan)）[B3-P204-23] Electrical, thermophysical and structural properties change for Gd
hydrides thin films controlled by gasochromic hydro/dehydrogenation*Riko Hirata1, Yuichiro Yamashita1,2, Takashi Yagi1,2, Makoto Kashiwagi1, Satoshi Takeya2,
Iesari Fabio3, Toshihiro Okajima1,3, Yuki Oguchi1, Naoyuki Taketoshi1,2, Yuzo Shigesato1（1. Aoyama Gakuin Univ. (Japan), 2. National Institute of Advanced Industrial Science andTechnology (Japan), 3. Aichi Synchrotron Radiation Center (Japan)）[B3-P204-24] Changes in Electrical and Thermal Conductivities of Sm Film by
Gasochromic Hydrogenation and Dehydrogenation*Miki Ueno1, Yuichiro Yamashita1,2, Takashi Yagi1,2, Makoto Kashiwagi1, Iesari Fabio3,
Toshihiro Okajima1,3, Yuki Oguchi1, Naoyuki Taketoshi1,2, Yuzo Shigesato1 （1. Aoyama
Gakuin Univ. (Japan), 2. National Institute of Advanced Industrial Science and Technology(Japan), 3. Aichi Synchrotron Radiation Center (Japan)）[B3-P204-25] Development of Power Flow Simulation of Distributed Hydrogen
System with Transient Characteristics Enabling Cost Analysis And
Control Study*Ryo Mitsui1, Yihuang Wang1, Toshitaka Iwase1 （1. Toyota Technical Development Corp.

©The Materials Research Society of JapanMRM2023/IUMRS-ICA2023(Japan)）[B3-P204-26] Zinc Aqueous Battery Anode Coated with Zinc Ion Conductive
Polymer for Suppression of Dendrite Growth and Inhibition of
Irreversible Hydrogen Evolution Reaction*Dae Yeop Jeong1 （1. Hanyang Univ. (Korea)）©The Materials Research Society of Japan

B3-P204-01

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanThe effective treatment of hydrogen boride (HB) sheets for the long-term
stabilization as the hydrogen storage
S. Ito1, M. Hikichi1, N. Noguchi2, M. Yuan2, Z. Kang2, K. Fukuda2, M. Miyauchi3, I. Matsuda4,*T. Kondo1,5,6
1

Department of Materials Science and Tsukuba Research Center for Energy Materials Science, Institute of Pureand Applied Sciences, University of Tsukuba, 2Graduate School of Pure and Applied Sciences, University ofTsukuba,, 3School of Materials and Chemical Technology, Tokyo Institute of Technology, 4Institute for Solid
State Physics (ISSP), The University of Tokyo, 5R&D Center for Zero CO2 Emission with Functional Materials,
University of Tsukuba, 6The Advanced Institute for Materials Research, Tohoku University,*
takahiro@ims.tsukuba.ac.jp (Corresponding author: University of Tsukuba, Ibaraki 305-8573, Japan)
Keywords: Hydrogen boride, hydrogen emission, hydrogen storage, long-term preservation
Two-dimensional hydrogen boride (HB), or borophane sheets, prepared by ion-exchange reactions frommagnesium diboride have been reported to have some interesting properties1)-3). HB sheets prepared by the ion
exchange method have a small amount of water-reactive parts4). In order to preserve the HB sheet for a long timeand use it for various purposes, it is important that it does not contain such a small amount of reactive parts. In
this study, we report on effective processing of HB sheets for long-term stabilization.5) As shown in Fig. 1, the
HB sheets were intentionally reacted with water, the highly reactive portion was removed, and the results werecompared and examined under different conditions over 9 months. The HB sheet obtained by mixing the HB
sheet and water and then redispersing the dried sample in acetonitrile and filtering showed excellent long-term
stability. Subsequent temperature-programmed desorption (TPD) experiments also showed that hydrogen was
stably released by raising the temperature (Fig. 2).

Fig. 1 Treatment of HB sheets for long-term stability. 5)

Fig. 2

H2-TPD of the original HB and treated HB kept in a refrigerator for 9 months after the treatment. 5)

References
1) S. Ito et al., Chem. Lett. 49, 789-793 (2020).
2) N. Noguchi et al., Molecules 27, 8261 (2022).
3) T. Goto et al., Commun. Chem. 5, 118 (2022).
4) K. I. M. Rojas et al., Commun. Mater. 2, 81 (2021).
5) S. Ito et al., Phys. Chem. Chem. Phys. (2023) in press (DOI: 10.1039/D3CP01256E).

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-01 -B3-P204-02

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Effects of High-temperature Heating of Hydrogen Boride Sheets Under
High-Hydrogen Partial Pressure
Yukihiro Yasuda1, Kazuho Goto1, Yuki Nakahara2, Reina Utsumi2, Hiroyuki Saitoh2, Satoshi
Nakano3, Shin-ichi Ito4, Miwa Hikichi4, Shin-ichi Orimo5,6, and *Takahiro Kondo4,5
1

Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki, 305-8577, Japan, 2 National
Institutes for Quantum Science and Technology, Hyogo, 679-5148, Japan, 3 National Institute for Materials Science,
Ibaraki, 305-0044, Japan, 4 Department of Materials Science and Tsukuba Research Center for Energy Materials
Science, Institute of Pure and Applied Sciences, University of Tsukuba, Ibaraki, 305-8577, Japan, 5 Advanced
Institute for Materials Research (WPI-AIMR), Tohoku University, Miyagi, 980-8577, Japan, 6 Institute forMaterials Research (IMR), Tohoku University, Miyagi, 980-8577, Japan*
takahiro@ims.tsukuba.ac.jp
Keywords: hydrogen boride sheets, hydrogen storage materials, two-dimensional materials
Two-dimensional (2D) materials are used in various fields such as electrode catalysts, photocatalysts,
electronics, optoelectronics, inserts and lubricants because of its superior properties. In 2017, experimental
realization of the hydrogen boride sheets (HB sheets) have been reported as a new 2D materials 1). HB sheets arecomposed of boron and hydrogen with stoichiometric 1:1. HB sheets theoretically take the structure of a sixmembered ring of boron bridged by hydrogen, but it is only a local structure. In fact, it is reported that HB sheets
have two types of bonds: one is three-center, two-electron (3c-2e) bond (B-H-B bond) and the other is two-center,two-electron (2c-2e) bond (B-H bond)2). HB sheets are expected to be used as a hydrogen storage material. It isestimated to exhibit a hydrogen storage of 8.5 wt% and releases hydrogen by heating. Not only itself but also
complexes with HB sheets are expected to exhibit a high level of hydrogen storage. For example, Li doped HBsheets theoretically indicate up to hydrogen storage of 11.57 wt%3). However, hydrogen dissociation temperatureof HB sheets is very wide because of its structural inhomogeneity,
so it is important to control its structure and evaluate hydrogendissociation characteristics. In this study, HB sheets were heatedunder extreme conditions such as high-hydrogen partial pressure
or ultrahigh pressure to induce structural changes while preventing
the decomposition and desorption of hydrogen from the HB
sheets.
The purpose of this study is to examine the effects of heating
the HB sheets and to clarify how the pressure and temperature
conditions affects the physical properties, especially hydrogendissociation characteristics of the HB sheets.
We have conducted heating of HB sheets under 573~1073 K
temperature condition and 5~11 MPa hydrogen partial pressure.
We have also conducted heating under ultrahigh pressure (3500
and 5000 MPa) without hydrogen.
Figure 1 shows M/z=2 thermal desorption spectroscopy (TDS)
of normal HB sheets and heated HB sheets. Intensity values arenormalized with the maximum value as 1. An interesting point isthat the peak of hydrogen dissociation shifts toward higher
temperatures as the heating temperature increases. Fouriertransformed
infraredabsorption(FTIR)
spectroscopy
measurements were also conducted to examine changes instructure, and there were not significant spectral differences
between the samples under different heating conditions in terms ofpeak positions of BHB and BH vibrational modes. In addition, Xray diffraction patterns of B2O3 Ⅰ and B2O3 Ⅱ were detected in
Figure 1. M/z=2 TDS of normal HB sheets and somesample heated at ultrahigh pressure.
References:
1) H. Nishino, et al., J. Am. Chem. Soc. 139 (2017) 13761-13769.
2) S. Tominaka, et al., Chem. 6 (2020) 406-418.
3) L. Chen, et al., Phys. Chem. Chem. Phys. 20 (2018) 30304-30311.

annealed HB sheets (Intensity values are normalizedwith the maximum value as 1)

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-02 -B3-P204-03

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanAbstract Guideline (Leave two lines for presentation number)

Controlling ultraviolet photo-induced H2 release rate by tuning B-H bonds
in free-standing borophane
Miwa Hikichi1, Junpei Takeshita2, Natsumi Noguchi3, Shin-ichi Ito1, Luong Thi Ta.4,5, Kurt
Irvin M. Rojas4, Iwao Matsuda6, Satoshi Tominaka7, Yoshitada Morikawa4, Ikutaro Hamada4,Masahiro Miyauchi2*, Takahiro Kondo1,8,9*
1

Department of Materials Science and Tsukuba Research Center for Energy Materials Science, Institute of Pureand Applied Sciences, University of Tsukuba, 2 Department of Materials Science and Engineering, School ofMaterials and Chemical Technology, Tokyo Institute of Technology, 3 Graduate School of Pure and Applied
Sciences, University of Tsukuba,4 Department of Precision Engineering, Graduate School of Engineering, Osaka
University, 5 Department of Chemistry, Institute of Environment, Vietnam Maritime University, Le Chan,
Haiphong, 6 Institute for Solid State Physics, The University of Tokyo, 7 Center for Basic Research on Materials(CBRM) , National Institute for Materials Science (NIMS), 8 Tsukuba Research Center for Energy Materials
Science, Institute of Pure and Applied Sciences and R&D Center for Zero CO2 Emission with Functional
Materials, University of Tsukuba, 9 The Advanced Institute for Materials Research, Tohoku University, .
mmiyauchi@ceram.titech.ac.jp, takahiro@ims.tsukuba.ac.jp
Keywords (Hydrogen boride, Hydrogen release, Boron, Two-dimensional materials ):Hydrogen boride (HB), a freestanding two-dimensional hydrogenated-borophene (borophane) polymorph, is
synthesized via ion exchange.1) HB sheets with a B/H atomic ratio of 1.0 have been confirmed to contain
three-center–two-electron B–H–B bonds and two-center–two-electron terminal B–H bonds.2) It has beenreported that H2 is released from HB sheets by UV irradiation.3) The optical properties of HB sheets are expected
to be tuned by changing the BHB/BH bond ratio which alters the electronic structure of HB sheets; however, thishas not yet been achieved. Herein, we demonstrate that controlling the BHB/BH bond ratio in the HB sheets ispossible without altering the hydrogen content by adjusting the volume of ion-exchange resin during synthesis,
thus enabling the tuning of the photoinduced H2 release under UV irradiation.4) Furthermore, the fluorescenceintensity correlates with the absorbance ratio of the BHB and BH vibrational modes in FT-IR spectra. Increasing
the BHB/BH bond ratio enhances the luminescence intensity, whereas reducing it enhances the photoinduced H2release rate under UV irradiation (Figure 1). The ability to control the BHB/BH bond ratio of HB sheets provides
new avenues for optimizing their properties for various applications, including hydrogen storage andphotocatalysis.

Figure 1 Increasing the BHB/BH bond ratio of borophane (hydrogen boride) sheets enhances the luminescence intensity, whereas reducing it
enhances the photoinduced H2 release rate under UV irradiation.4)

References
1) Nishino, H. et al. J. Am. Chem. Soc. 139, 13761–13769 (2017).
2) Tominaka, S. et al., Chem 6, 406-418 (2020).
3) Kawamura, R. et al., Nature Commun. 10, 4880 (2019).
4) Hikichi, M. et al., submitted.

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-03 -B3-P204-04

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Evaluation of NH3 adsorption properties on hydrogen bolide sheets
Kosei Fukuda1, Shin-ichi Ito2, Miwa Hikichi2, Iwao Matsuda3, Takahiro Kondo*2,41

Graduated school of Pure and Applied Sciences, University of Tsukuba, 2 Department of Materials Science andTsukuba Research Center for Energy Materials Science, Institute of Pure and Applied Sciences, University ofTsukuba, 3Institute for Solid State Physics, The University of Tokyo, 4The Advanced Institute for Materials
Research, Tohoku University*takahiro@ims.tsukuba.ac.jp
Keywords: Ammonia adsorption, boron, borophane, hydrogen borides.
Hydrogen boride (HB) sheets are two-dimensional materials firstly synthesized in 20171, which consist ofnegatively charged boron and positively charged hydrogen at a molar ratio of 1:1. In this study, we focused on thepositively charged hydrogen in HB sheets and aimed to clarify whether the adsorption of NH3 molecules occurs
or not, and its mechanism. HB sheets were synthesized as reported previously1. We then exposed the HB sheets toammonia vapor. Specifically, the small bottle with HB (20 mg) was put in the large bottle with 10 mL ammonia
water and the large bottle was closed. After specific time had passed, we picked out the small bottle and heated it
under vacuum for 30 min under 343 K to dry and got the dried sample. The obtained sample was examined byweight measurement, Fourier transform infrared absorption spectroscopy (FT-IR), temperature programmed
desorption mass spectrometry (TPD-MS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS).
The mass of the dried sample was found to increase withincreasing exposure time of ammonia water as shown in Figure 1.
The maximum mass change of the sample was about 180%. Thisis larger amount compared to the case of pure water exposure(137%), indicating that NH3 is adsorbed on HB sheets even after
343 K heating. In FT-IR spectra, the distinct peak was observed
near 2500 cm-1 for original HB sheets as shown in Fig. 2, which
can be attributing to the terminal B-H stretching vibrational mode.2

Fig. 1 Mass change of the HB sheets after exposureof ammonia water vapor and pure water.

The absorption peak position was found to shift about 40 cm-1 tolower wavenumber for the sample after the exposure of ammonia
water vapor followed by drying, indicating that B-H bond getsweakened when NH3 is absorbed on the HB sheets. In TPD-MS,
NH3 (m/z=17) desorption peaks were observed at 450 K and 640
K. Based on the analysis of other samples, the former peak (450K) could be ascribed to the decomposition of ammonium borate
while the latter peak (640 K) could be ascribed to the NH3
adsorbed on the HB sheets. Detail of NH3 adsorption will bepresented.
Fig. 2 FT-IR spectrum of HB sheets before andafter the exposure to ammonia vapor with 2-144 h,followed by drying.

References
1. Nishino, H. et al. J. Am. Chem. Soc. 139, 13761 (2017).
2. Tominaka, S. et al. Chem 6, 406 (2020).

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-04 -B3-P204-05

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Investigation on the Catalytic Performance of Hydrogen Boride for theConversion of Ethanol and Ethanol Solution*

Zihao Kang1, Shin-ichi Ito2, Miwa Hikichi2, Takahiro Kondo2,3

1

Graduate School of Pure and Applied Sciences, University of Tsukuba, 2 Department of Materials Science andTsukuba Research Center for Energy Materials Science, Institute of Pure and Applied Sciences, University ofTsukuba, 3 Advanced Institute for Materials Research (WPI-AIMR), Tohoku University*
takahiro@ims.tsukuba.ac.jp
Keywords: Two-dimensional catalyst, Hydrogen Boride, Ethanol conversion
The two-dimensional nano sheet materials obtained by the stripping of layered materials, due to their large
surface area and special electronic state, are expected to be used in various fields such as catalysts and electronic
devices. In previous studies in our laboratory, it has been proved that hydrogen boride (HB) sheets play a role asa solid acid catalyst1, 2 and the sheets are chemically stable against water.3 Specifically, in the presence of HB
sheets, ethanol was found to be converted to ethylene with high selectivity.1 Moreover, there was an indicationthat mixture of water in ethanol may change the reaction product, i.e., the selectivity of ethanol conversion may
control by controlling water content. In this study, therefore, effects of water mixture for the ethanol conversion
by hydrogen boride sheets will be examined.
The prepared HB sheets4 were loaded into a fixed bed reactor. As pre-treatment, the sample was heated at
300 °C in argon gas environment for 1 hour and cooled to room temperature, then reheated to 300 °C withintroducing ethanol. The conversion of ethanol was found to increase at 180 ℃ with heating. Its selectivity toethylene is more than 80% when ethanol was flow without adding water at 300 ℃ as shown in Figs. 1 and 2. The
W/F (weight of catalyst/ethanol flow rate) was changed by adjusting the ethanol flow rate. It was found that
under different W/F conditions, the product selectivity did not change (Fig. 1), but the conversion rate of ethanolchanged (Fig. 2). Next we tested HB with 15 wt% ethanol solution. We found that the conversion and selectivity
significantly changed with the addition of water to ethanol (Figs. 3 and 4). The detail results will be discussed inpresentation.

Fig. 1. Selectivity of HB with pure ethanol vs time

Fig. 2. Ethanol conversion of HB with pureethanol vs time

Fig. 3. Selectivity of HB with 15 wt%
ethanol solution vs time

Fig. 4. Ethanol conversion of HB with 15 wt%
ethanol solution vs time

References:
1) A. Fujino, et al., ACS Omega. 4 (2019) 14100-14104.
2) A. Fujino, et al., Phys. Chem. Chem. Phys. 23 (2021) 7724-7734.
3) K. Rojas, et al., Commun. Mater. 2 (2021) 81
4) H. Nishino, et al., J. Am. Chem. Soc. 139 (2017) 13761.
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-05 -B3-P204-06

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Electronic and optical properties of the hydrogen boride sheet from the
many-body perturbation theory
Luong Thi Ta1, Yoshitada Morikawa1, *Ikutaro Hamada1
1

Department of Precision Engineering, Graduate School of Engineering, Osaka University.
ihamada@prec.eng.osaka-u.ac.jp
Keywords: Hydrogen boride, GW, electronic structure, optical spectra, 2D.
*

The hydrogen boride (HB) sheet is a new member of two-dimensional (2D) boron-based materials andpossesses great potential in electronic and catalytic applications due to its facile synthesis, chemical stability, andinteresting optoelectronic properties.1) However, the predicted different electronic structures (i.e., semimetallic
versus semiconductor) depend on the level of theory and are controversial, which calls for a more rigorous
calculation of the electronic structure.2,3)
In this work, we used many-body perturbation theory to calculate a more accurate band structure of the HB
sheet than those of the conventional density functional theory. We used the perturbative GW (G 0W0) calculation
without the plasmon-pole approximation (i.e., full frequency G0W0). We carefully study the convergenceparameters, such as the cutoff energy and the number of unoccupied states to calculate the dielectric constant andobtained well-converged quasiparticle energies. We found that the HB sheet possesses a semimetallic electronic
structure, which supports the finding based on the semilocal DFT calculations. Furthermore, we calculated theoptical spectra based on the G0W0 quasiparticle energy and the random-phase approximation, which agrees wellwith the photoabsorption measurement and explains the experimental findings. 4)

Fig. 1. Band structure and density of states (DOS) of the HB sheet obtained at the G0W0 level of theory (dot), along with that obtained at the
PBE level of theory (solid line), and the geometry of HB.

References
1) H. Nishino et al., J. Am. Chem. Soc. 139, 13761–13769 (2017)2) R. Kawamura et al., Nat. Commun. 10, 1–8 (2019)3) Li Shao, Physical Chemistry Chemical Physics 14, 7630-7634 (2019).
4) L. T. Ta, Y. Morikawa, and I. Hamada (submitted).

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-06 -B3-P204-07

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Interplay of Hydrogen Boride Sheets with Water: Insights into Surface andEdge Stability*

Kurt Irvin M. Rojas1, Yoshitada Morikawa1,2, Ikutaro Hamada1

1

Department of Precision Engineering, Graduate School of Engineering, Osaka University, 2 Research Center for
Precision Engineering, Graduate School of Engineering, Osaka University*
krojas@cp.prec.eng.osaka-u.ac.jp
Keywords: Hydrogen boride, Density functional theory, Surface, Edge, Stability
Two-dimensional hydrogen boride (HB) sheets with a 1:1
stoichiometric ratio of boron and hydrogen have been recently
synthesized from magnesium diboride (MgB2) via ion-exchange process(Fig. 1).[1] Recent investigations have revealed remarkable properties of
HB sheets, including outstanding solid-acid catalytic activity, semimetalelectronic character, high sensitivity to gases, and the ability to releasehydrogen under ultraviolet light. Consequently, the HB sheet holds great
promise as a material for various applications such as batteries, gas andlight sensors, and electrodes.[2] Nonetheless, the potential instability of
HB sheets remain a concern due to the well-known reactivity of theparent material, MgB2, and boron hydrides, which are susceptible toFig 1. HB sheet modelhydrolysis in the presence of water – a common substance in typicaloperating environments.
In this investigation, our focus was to explore the interaction between hydrogen boride sheets and waterusing density functional theory calculations.[3] Specifically, we concentrated on studying the surface and edge
interactions. Regarding the surface interactions, we examined both pristine and vacancy-defected models,observing their behavior upon contact with water. Our findings revealed an exceptionally weak interaction
between water and HB sheet, displaying no evidence of chemical bonding or substantial structural deformationthat typically onsets a hydrolysis reaction. However, we observed that the interaction strength increased
proportional to the size of the defect, albeit still considerably weak. We attribute the stability of the HB sheets to
the robust B-B bonding inherent in the sheet’s
honeycomb structure.
The investigation of the edges becomes particularly
intriguing since the stability advantage offered by theB-B network is only partially present in these regions.
Upon closer examination, we discovered a notable
distinction in not only the adsorption environment forwater but also the inherent structure of HB itself
depending on the edge orientation – armchair or zigzag.
With only a passivation layer for the boron edge atoms,
Fig 2. H2O on (A) Zigzag edge and (B) H-vacant armchair edge
we analyze the structure first. Similar to the HB sheet’s
honeycomb structure, the armchair edges remain intact; however, the zigzag edge undergoes significant
deformation, forming fringe-like edges (Fig. 2A). This observation directly indicates that the edges exhibit
weaker B-B support compared to the surface. Subsequently, when water was introduced, we obtained adsorptionenergies similar to that of surface-adsorbed water. This phenomenon could be attributed to the presence ofhydrogen termination that passivates the edge. To explore the reactivity of a non-passivated HB edge, we
induced a hydrogen vacancy on the armchair edge. Remarkably, when water adsorbed onto the H-vacantarmchair edge, multiple indicators such as adsorption energy, density of states, and charge density difference
revealed evidence of chemical bonding (Fig. 2B). Notably, the bonding between the oxygen and boron wasobserved, signifying the initiation of the hydrolysis reaction in HB sheets.
References:
1) H. Nishino, et al., J. Am. Chem. Soc. 139, 13761 (2017).
2) T. Goto, et al., Commun. Chem. 5, 118 (2022).
3) K. I. M. Rojas, et al., Commun. Mater. 2, 81 (2021).

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Investigation of carrier properties of rhombohedral boron monosulfide andchanges in properties due to impurity doping
N. Watanabe1, K. Miyazaki2, M. Toyoda3, K. Takeyasu4,5, N. Tsujii6, H. Kusaka1, A.
Yamamoto7, S. Saito3, M. Miyakawa6, T. Taniguchi6, T. Aizawa6, T. Mori6, M. Miyauchi2, T.
Kondo*4,5,8
1

Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan, 2 Departmentof Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute ofTechnology, 3 Department of Physics, Tokyo Institute of Technology, 4 Tsukuba Research Center for Energy
Materials Science, Department of Materials Science, Institute of Pure and Applied Sciences, University ofTsukuba, 5 R&D Center for Zero CO2 Emission with Functional Materials, University of Tsukuba, 6 ResearchCenter for Materials Nanoarchitectonics, National Institute for Materials Science, 7 Institute of Engineering,Tokyo University of Agriculture and Technology, 8 Advanced Institute for Materials Research, Tohoku
University*
takahiro@ims.tsukuba.ac.jp
Keywords: 2D material, Boron, Nonmetal material, High pressure and high temperature synthesis
Due to their unique properties, two-dimensional materials
are used in a wide range of applications, such as electronic
devices and catalysts. The polymorphic properties ofboron-based materials make them suitable for thedevelopment of boron-based two-dimensional materials.
Among them, rhombohedral boron monosulfide (r-BS) (Fig.
1) has attracted much attention in recent years because of its
unique layered structure similar to transition metal
dichalcogenides and layer-dependent band gap [1]. However,experimental evidence that identifies the type of charge
carriers in r-BS semiconductors is lacking. In this study, we
synthesized r-BS and evaluated its performance as asemiconductor by measuring the Seebeck coefficient andphoto-electrochemical responses [2].
In both measurements, properties characteristic of p-typesemiconductors were observed (Fig. 2), indicating that thesynthesized r-BS is a p-type semiconductor. In addition,
Fourier transform infrared absorption spectroscopy showed a
Fano resonance, which is attributed to the Fano resonancebetween the E(2) (TO) phonon mode and the electrons in the
r-BS band structure, indicating that the synthesized r-BS is
intrinsically doped with p-type carriers. These results provide
experimental evidence for future applications of r-BS.
To investigate the changes in the properties of r-BS due toimpurity doping, we recently synthesized carbon-doped r-BS
as an additional experiment. Measurements of the propertiesof this material and a discussion of the r-BS carrier will bementioned on the day of the session.

References:[1] H. Kusaka, et al., J. Mater. Chem. A. 2021, 9, 24631.
[2] N. Watanabe, et al., Molecules 2023, 28, 1896.
[3] K. Momma, F. Izumi, J. Appl. Crystallogr. 2011, 44, 1272.

Fig. 1. The structure of r-BS [1-3].

Fig. 2. Temperature dependence of
the Seebeck coefficient of thesynthesized r-BS [2]MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-08 -B3-P204-09

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Edge-dominated Hydrogen Evolution Reactions in Ultra-narrow MoS2
Nanoribbon Arrays
Ding-Rui Chen1,2,3, Hao-Ting Chin1,2,3, Mario Hofmann4, *Ya-Ping Hsieh1,2,3
1International Graduate Program of Molecular Science and Technology, National Taiwan University, Taipei,
10617, Taiwan, 2 Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan, 3
Molecular Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei,
10617, Taiwan, 4 Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
*
yphsieh@gate.sinica.edu.tw
Keywords: MoS2, nanoribbons, Hydrogen evolution reaction, ultranarrow, dry etching
Future energy generation and storage requirements emphasize the importance of high-performanceelectrocatalysis. MoS2 edges exhibit ideal energetics for hydrogen evolution reactions (HER) if challenges intheir kinetics are addressed. We here investigate the emergence of edge-dominated electrochemical reaction
kinetics in ultra-narrow MoS2 nanoribbons. A templated subtractive patterning process (TSPP) that yielded large
arrays of MoS2 nanoribbons that served as a powerful platform. Nanoribbons with widths below 30nm exhibit
significantly increased reaction kinetics, as evidenced by a ~200-fold enhanced turn-over frequency, an 18-foldincreased exchange current density, and a 38% decreased Tafel slope. (Fig. 1) These improvements are due to anincreased charge transfer efficiency from the basal plane toward the edge sites. Photo-electrocatalytic
measurements and carrier transport simulation reveal the impact of suppressed band bending in nanoribbons
below the depletion width in achieving edge-dominated HER. Our results demonstrate the potential of
confinement in electrocatalysis and provide a universal route toward nanoribbon-enhanced electrochemistry.

Fig. 1. Efficient hydrogen evolution reaction in ultra-narrow MoS2 nanoribbon arrays

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Diffusion-restricted Cation Exchange Synthesis Of UltrafineElectrocatalyst For Hydrazine Assisted Hydrogen ProductionRh

Hak Hyeon Lee1, Ji Hoon Choi1, *Hyung Koun Cho1
1

School of Advanced Materials Science and Engineering, Sungkyunkwan University, 2066 Seobu-ro,
Jangan-gu, Suwon-si, Gyeonggi-do 16419, Republic of Korea*
chohk@skku.edu
Keywords: Cation Exchange Synthesis, Rh Electrocatalyst, Hydrazine Oxidation Reaction, Hydrogen Production
Water splitting driven by renewable energy is a promising hydrogen production method without carbon
emission. However, oxygen evolution reaction still diminishes the total cell’s efficiency due to its large
overpotential and sluggish kinetics.1) Rh is a highly active catalyst for the electrochemical oxidation of hydrazine,
which has the potential to replace the oxygen evolution reaction and lower operating voltage. 2) Unfortunately, Rh
is an expensive noble metal, but only few studies have explored ways to reduce the amount of Rh used. This
study proposes using the diffusion-restricted cation exchange (CE) process to decrease the mass of inactive Rh
and improve mass activity.3) By immersing the NiOOH substrate in a Rh3+ solution, Rh3+ atoms are exchanged
with Ni3+ atoms on the surface, RhOOH forms on the outer layer. The RhOOH layers are reduced again into
metallic rhodium by an electrochemical reduction process, resulting in fine Rh nanoparticles less than 2 nm insize. This approach can suppress Rh aggregation, doubling the mass activity for electrocatalytic hydrazineoxidation compared to conventional electrodeposited Rh catalysts. As a result, the proposed CE-derived Rh
catalyst shows stability for over 36 hours in the two-electrode hydrazine splitting system and allows thehydrogen production by single CIGS solar cell.

Figure 1. The proposed synthetic process of Rh electrocatalyst based on diffusion-restricted cation exchange andcorresponding electrochemical hydrazine oxidation performance with SEM images.

References
1) M. Wang, L. Zhang, Y. He, H. Zhu, J. Mater. Chem. A 9, 5320–63 (2021).
2) D. A. Finkelstein, R. Imbeault, S. Garbarino, L. Roue, D. Guay, J. Phys. Chem. C 120, 4717 (2016).
3) H.H. Lee, D.S. Kim, S. Sarker, J.H. Choi, H.S. Lee, H.K. Cho, Energy Environ. Mater. 0, e12556 (2023).

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-10 -B3-P204-11

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Photocatalytic Hydrogen Production from Na2S/Na2SO3 Solution with
Visible Light Responsible g-C3N4/(CuAg)0.1In0.2Zn1.6S2*S. Asakuma1, M. Furukawa1, I. Tateishi,2 H. Katsumata,1 S. Kaneco1
1

Department of Applied Chemistry, Graduate School of Engineering
Global Environment Center for Education & Research, Mie University, Tsu, Mie 514-8507, Japan.
*
423M303@m.mie-u.ac.jp
Keywords: Photocatalytic hydrogen production, (CuAg)0.1In0.2Zn1.6S2, visible light irradiation, g-C3N4,
2[Introduction] Great progress has been achieved in photocatalytic H 2 production technologies since thephotochemical splitting of water over a TiO2 electrode was first reported by Fujishima et al. So far, most reported
photocatalysts have large band gap energy (Eg > 3.0 eV) and so they are only active under ultraviolet light, which
occupies only 5% of the solar spectrum. Designing visible-light-driven photocatalysts with high photocatalytic
activity and visible-light absorption to make full use of the solar spectrum has therefore been an important research
focus. In this study, (CuAg)0.1In0.2Zn1.6S2 was used as an inexpensive photocatalyst to improve and enhance the H 2
production efficiency under visible light irradiation.
[Experimental] The photocatalyst (CuAg)0.1In0.2Zn1.6S2 was prepared by hydrothermal synthesis. AgNO3 (1 mmol)
0.169 g, Zn(NO3)2•6H2O (16 mmol) 4.752 g, and In(NO3)2 (2 mmol) 0.709 g were dissolved in 10 mL distilledwater (pure water), and nitrogen was purged into the solution for 30 minutes. To the solution were added 0.099 gof CuCl (1 mmol), 1.37 g of CTAB (3.76 mmol), and 6.010 g of TAA (80 mmol). The resulting solution washeated in an autoclave and then was naturally cooled. The product was centrifuged and washed twice with distilledwater and ethanol. After the vacuum drying at 60℃ for 24 h, (CuAg)0.1In0.2Zn1.6S2 was obtained. The catalytic
activity of the photocatalyst was evaluated by hydrogen production. 50 mg of photocatalyst, Ru standard solution(1000 ppm), and a mixture of sodium sulfide (0.5 M) and sodium sulfite (0.4 M) were added into a reaction vessel.
The solution volume was 40 mL. One wt% of CuO, ZnO, diamond, and g-C3N4 were added as a second co-catalyst.
The solution was dispersed for 3 minutes under an ultrasonic irradiation. The resulting solution was then irradiatedwith light using an Xe lamp for 6 h while stirring, and the amount of hydrogen production was measured by gas
chromatography-TCD after 3 and 6 hours.
[Results and Discussion]
The hydrogen production with second cocatalyst became worse except for g-C 3N4.
The addition of g-C 3N4 improved thephotocatalytic H 2 production in the presenceof Ru catalyst. The effect of the amount of
g-C 3N4 in the presence of Ru wasinvestigated. The H2 amount with 0.5 wt%
g-C 3N4 was greatest. The addition of g-C 3N4
in the presence of Ru improved the amountof hydrogen production.
The mechanism of H2 production isshown in Fig. 1. When a photocatalyst is
irradiated with visible light, electrons in thevalence band are excited in the conductor,
forming photoexcited electrons and holes.
Fig. 1. Mechanism of hydrogen production with
The generated holes efficiently oxidize S2g-C3N4/(CuAg)0.1In0.2Zn1.6S2 in Na2S/Na2SO3 aqueous solution.
and SO 32- to produce protons, suppressing
the recombination of photoexcited electrons and holes and promoting charge separation. The photoexcitedelectrons in the conduction band are transferred to g-C 3N4 and then to Ru 2S3 supported on the photocatalyst.
The electrons can reduce H+ and efficiently generates hydrogen. Furthermore, some Ru 2S3 is converted to
RuS2, and hydrogen is generated by the redox cycle between Ru 2S3 and RuS2.
[Conclusion]
The effective second co-catalyst was g-C3N4 in the production of hydrogen from Na2S/Na2SO3 solution undervisible light irradiation with Ru/(CuAg)0.1In0.2Zn1.6S2. The best amount of g-C3N4 was 0.5 wt%, at which thehydrogen production rate was 1447 μmol･g-1 ･h-1. The present work can facilitate the research for highly
efficient and stable water splitting photocatalysts.

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Construction of highly active photocatalytic system using edge-grafted gC3N4*

M. Yoshimura1, H. Katsumata1, I. Tateishi2, M. Furukawa1, S. Kaneco1

1

Department of Applied Chemistry, Graduate School of Engineering, Mie University, Tsu, Mie, Japan.
Global Environmental Center for Education & Research, Mie University, Tsu, Mie, Japan.
*
423M361@m.mie-u.ac.jp
Keywords: g-C3N4, photocatalyst, pyridine, O-dope, hydrogen evolution2

To achieve a decarbonized society, next-generation clean energy is attracting attention, and hydrogen energy,
one of them, is a clean and sustainable energy with high energy density. Currently, hydrogen consumed
industrially is mainly produced by reforming fossil fuels (coal and natural gas), which consumes high energy andemits CO2. In contrast, photocatalytic water splitting can produce hydrogen using water and solar energy, and thereaction takes place at room temperature and pressure, making it an environmentally friendly and simple method.
Graphitic carbon nitride (g-C3N4) is a metal-free photocatalyst and has the advantages of visible light
responsiveness, low cost, and excellent photochemical stability. However, its performance is severely limited by
the immediate recombination of photogenerated electron-hole pairs. In this study, by introducing a pyridine ring
and an oxygen atom into the g-C3N4 framework, we have improved the photocatalytic activity by extending theabsorption wavelength range and increasing the charge separation efficiency.
Photocatalytic g-C3N4 (CN) samples were synthesized by direct calcination of urea in air at 550 °C for 4
hours . POCN samples edge-grafted with pyridine rings and oxygen atoms were prepared as follows. urea mixed
with 2-aminopyridine and ammonium formate were uniformly ground and the collected mixture was placed in a
crucible with a lid and heated as in the CN synthesis process above. PCN sample obtained by mixing only urea
and 2-aminopyridine and an OCN sample obtained by mixing only urea and ammonium formate were also
prepared and compared for hydrogen evolution.
The experimental procedure for hydrogen production
Table 1. Experimental conditions
is as follows. 40 mg of catalyst was placed in a reaction
Photocatalyst
Photocatalysts (40 mg) / Pt (0.8 mg : 2.0 wt%)
vesselwithwater,
triethanolamine,andhexachloroplatinum acid, and nitrogen purged for 30
Water (35.2 mL) , TEOA (4 mL : 10 vol%),MediumH₂PtCl₆ (0.8 mL : 1000 ppm)
minutes before light irradiation. A xenon lamp was usedas the light source, and the reaction system was exposed
ReactorPyrex glass vessel (Volume:123 mL)
to light for 6 hours through a 420 nm cutoff filter andmeasured by gas chromatography. Characterization was
Temperature
Room temperature (25 ℃)
also performed to confirm photocatalytic activity.
Light source
Xenon lamp (λ≧420 nm 10 mW/cm²)
Photocatalytic activity results show that CN had no
confirmed hydrogen production, while PCN, OCN, andAnalysis
Gas chromatography (TCD)
POCN had the high hydrogen production rates of 16µmol g-1 h-1, 100 µmol g-1 h-1, and 202 µmol g-1 h-1,
respectively. PL measurements showed a decrease influorescence due to the introduction of oxygen; EIS
measurements showed that co-dope of pyridine and oxygento carbon nitride decreased the charge resistance to thesolution interface. These results of enhanced photocatalytic
activity of POCN suggest that electron delocalization by
substitution of oxygen atoms results in suppression ofelectron-hole pair recombination. In addition, the pyridine
ring introduced at the end of the carbon nitride skeleton
functions as an electron donor, improving the charge transfer
efficiency.
This indicates that the dual modification of the pyridine ringand oxygen synergistically enhances the photocatalytic
activity of g-C3N4.
Fig. 3. EIS Nyquist plots of CN, PCN, OCN and POCN..

Reference
1) C. Li, H. Wu, D. Zhu, T Zhou, M. Yan, G. Chen, J. Sun, G. Dai, F. Ge, H. Dong, Appl. Catal. B: Environ. 297,
120433(2021).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-12 -B3-P204-13

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Study on LaFeO3 photocathode for long-term stable photoelectrochemical
water splitting*

Hyunwoong Seo1, Kyumi Han1, Min-Kyu Son2

1

Department of Energy Engineering, Inje University, Gimhae, Gyeongsangnamdo, Korea, 2 Korea Institute of
Ceramic, Jinju, Gyeongsangnamdo, Korea*
hwseo@inje.ac.kr
Keywords: Photoelectrochemical water splitting, LaFeO3, Green hydrogen

Most of conventional hydrogen production methods were based on unenvironmental-friendly processes suchas natural gas steam reforming, coal gasification, and so on. The more the hydrogen demand increases, the more
green hydrogen production techniques are necessary. Photoelectrochemical (PEC) water splitting is one of very
attractive solutions for eco-friendly hydrogen production.1-3 The photo-generated electrons and holes participate
in the hydrogen evolution reaction at the photocathode and the oxygen evolution reaction at the photoanode,
respectively. PEC water splitting needs only solar energy not any environmental-pollutional resources. However,it has some limits in technical aspects. Especially, long-term stability is one of significant issues in PEC water
splitting. Most of semiconductor photocathodes reported so far were poor stability against aqueous solutions.
Lanthanum iron oxide (LaFeO3) is a promising p-type semiconductor to overcome this drawback because of its
photocatalytic capability, optical characteristics and good stability in an aqueous solution. In addition, it is visible
light-responsive, enabling the utilization ofabundant solar energy because its band gap energy
is around 2.1–2.6 eV.4-6 Furthermore, it does notcontain any copper component so that it is resistantto photocorrosion in aqueous solutions. Here, acrystalline LaFeO3 thin film was prepared by radio
frequency magnetron sputtering deposition. It wasused as a PEC photocathode after post-annealing
treatment in air. Figure 1 shows XRD patterns of
sputtered LaFeO3 film according to the postannealing temperatures and SEM cross-view imageof the crystalline sputtered LaFeO3 film. The
morphological, compositional, optical andelectronic properties of LaFeO3 photocathode wereanalyzed and optimized. It exhibited stable PEC
performance in a strong alkaline solution during
PEC operation without any protection layers. As aresult, it was concluded that the crystalline LaFeO3
Fig. 1. XRD patterns of sputtered LaFeO3 film with/without the postwould be feasible to apply as a long-term stableannealing process at different temperatures and SEM image of LaFeO3
PEC photocathode. Detailed results and analysis
film with the post-annealing process at 550 °C (inset).
will be presented on the conference site.

References
1) M. G. Walter, E. L. Warren, J. R. McKone, S. W. Boettcher, Q. Mi, E. A. Santori and N. S. Lewis, Chem.
Rev., 110, 6446–6473 (2010).
2) C. Jiang, S. J. A. Moniz, A. Wang, T. Zhang and J. Tang, Chem. Soc. Rev., 46, 4645–4660 (2017).
3) J. H. Kim, D. Hansora, P. Sharma, J.-W. Jang and J. S. Lee, Chem. Soc. Rev., 48, 1908–1971 (2019).
4) S. N. Tijare, M. V. Joshi, P. S. Padole, P. A. Mangrulkar, S. S. Rayalu and N. K. Labhsetwar, Int. J. Hydrogen
Energy, 37, 10451–10456 (2012).
5) M. D. Scafetta, A. M. Cordi, J. M. Rondinelli and S. J. May, J. Phys.: Condens. Matter, 26, 505502 (2014).
6) K. Peng, L. Fu, H. Yang and J. Ouyang, Sci. Rep., 6, 19723 (2016).

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Electrodeposited Cu2O with a Reduced Interfacial Amorphous Phase Using
Artificially Oriented ITO and Their Enhanced Photoelectrochemical Solar
to H2 Efficiency
Ji Hoon Choi1, Hak Hyeon Lee1, *Hyung Koun Cho1
1

Sungkyunkwan University
chohk@skku.edu
Keywords: Photoelectrochemical cell, Hydrogen evolution reaction, Interface engineering*

The Insufficient light harvesting, quick charge recombination, and sluggish water reduction kinetics severely
limit the efficiency of photoelectrochemical (PEC) water splitting. A photoelectrode needs to be purposefully
constructed since the existence of amorphous phases in the interfaces makes it difficult to overcome these innate
restrictions. Here, we used synthetic techniques to manipulate the crystallographic orientation of indium tinoxide (ITO) in order to identify the orientation that has the least amount of lattice misfit at the Cu 2O interface.
This considerably reduced the amount of amorphous phase during the first stages of electrodeposition nucleation.
By establishing an ideal interface with preferentially developed (111) oriented Cu 2O and minimizing theamorphous area, the [222]/[400] mixed orientation ITO largely exposed the {400} surface planes and accelerated
charge transfer. In order to theoretically confirm which plane is more active for building the photoactivation
layer, the ITO surface energy was also estimated using the density functional theory. The ITO/Cu 2O/Al-dope
ZnO/TiO2/Rh-P device, which was rationally built with each layer performing a distinct function, produced aneffective solar-to-hydrogen conversion photocathode with a photocurrent density of 8.23 mA cm -2 at 0
VRHE under AM 1.5 G irradiation.
References (Example: non-mandatory, 10-point) :1) J. H. Choi, H. Seok, D. Sung, D. S. Kim, H. H. Le, S. Hong, H. Kim, H. K. Cho, J. Eng. Chem. 82, 277-286(2023)MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-14 -B3-P204-15

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan[Abstract Guideline (Leave two lines for presentation number)]

Simulation of Water Electrolysis of Polymer Electrolyte Membranes
Kentaro Haraguchi1, Ryo Mitsui1, *Hidekazu Yokomakura1,
1

Toyota Technical Development Corporation
hidekazu.yokomakura@mail.toyota-td.jp
Keywords: PEM, Electrolysis, Simulation, Hydrogen*

For climate change issues, water electrolysis, which is one of a hydrogen gas generation method from carbon
free electric power, is researched and developed for increasing in performance and decreasing costs. Polymer
electrolyte membranes type as proton exchange membranes (PEM) electrolysis have similar structure to proton
exchange membrane type of Fuel Cell.
It is necessary to utilize iridium as high cost catalysis for PEM electrolysis on the market. So it is important
to develop efficient device. Then a water electrolysis cell is in experiment and simulation1.
The efficiency of electric power generation is believed to be hindered by stagnant gas near porous feeder. Thisgas covers the electrode and prevents water from coming into contact with electrode2. Additionally, there is aconcern that the generated gas will accumulate downstream as it flows along the water channel1.
We refer fuel cell model3 and introduce each simulation of fluid, thermal conduction and flow rate, alongwith an equivalent circuit model. We show the simulation model in fig. 1, and the thickness of each area ofwater electrolysis cell in table 1. The simulations are combined and we calculate the volume ratio of liquid andfluid, saturation ratio. Furthermore, the simulation
Table 1. Water electrolysis sizemodel incorporates the effect of stagnant gas thatNo
Item
Thickness[cm]1
anode channel(oxygen electrode)
0.03
covers the electrode. Our model in fig. 2
2anode porous feeder
0.05
demonstrates an increase in the saturation ratio and3
proton-exchange membrane(PEM)
0.0178a decrease in the fluid flow rate of oxygen and4cathode porous feeder
0.05hydrogen compared to a simulation model that does5
cathode channel(hydrogen electrode)0.03
not consider the effect of stagnant gas. This
indicate that our model can qualitatively represent
the effect of stagnant gas covering the electrode.
3.16[cm]
The sections is distinguished each other with color.
anode channel(oxygen electrode)
anode porous feeder
proton-exchange membrane(PEM)
Viewcathode porous feeder
larger withboundaries cathode channel(hydrogen electrode)Fig. 1. Water electrolysis with proton-exchange membrane

Ratio

References :1) T. Murakami, T. Hikosaka, T. Aranaga, K. Onda,
K. Ito, IEEJ Transactions on Power and Energy
120-B(2), 256-263 (2000).
2) D. L. Fritz, J. Mergel, D. Stolten, ECS
Transactions 58(19), 1-9 (2014).
3) H. Masuda, K. Ito, Y. Kakimoto, K. Sasaki,
Transactions of the JSME (in Japanese) Vol. 73, No.
727, 855-862 (2007).

Fig. 2. Saturation and material flow rate of bubble
effect model(wt) normalized by result of without
bubble effect(wo).

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Eco-friendly Electrochemical Ammonia Oxidation of NiCuP Electrocatalyst
for Hydrogen Production
Chanmin Jo1, Subramani Surendran1, Pildo Jung2, Dongjin Lee2, Il Goo Kim2 and *Uk Sim1,2
1

Hydrogen Energy Technology Laboratory, Korea Institute of Energy Technology (KENTECH), 200
Hyeoksin-ro, Naju, Jeonnam 58330, 2 Research Institute, NEEL Sciences, INC., 58326 Jeollanamdo, Republic of
Korea*
usim@kentech.ac.kr (Uk Sim)
Keywords : Ammonia electrolysis, Ammonia Oxidation, Nickel copper phosphide, Hydrogen carrier, Hydrogenproduction
As a means to realize carbon neutrality, hydrogen, an alternative energy source, is in the limelight. However,since hydrogen is difficult to liquefy for transportation, it is important to use a hydrogen carrier that is
relatively convenient to transport and has a high hydrogen storage capacity. Ammonia has a high potential for
use as a hydrogen carrier, and it can theoretically convert hydrogen with low reaction energy throughelectro-oxidation, and COx is not generated as a product. In order to replace precious metals such as Pt, Ru,
and Ir, research on non-noble metal catalysts is being actively conducted. In this work, a NiCuP electrocatalyst,
a non-precious metal-based catalyst, was synthesized, and electrochemical analysis was performed onammonia electrolysis, including ammonia oxidation reaction and hydrogen generation based on theelectrochemical ammonia oxidation reaction was measured. NiCuP electrocatalyst presents the possibility ofusing ammonia as a hydrogen carrier for non-precious metal-based electrocatalysts.

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-16 -B3-P204-17

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Membrane Reactor Combining V-based Hydrogen Permeable Alloy
Membrane with Ammonia Decomposition Catalyst for Direct High-Purity
Hydrogen Production from Ammonia*

K. Omata1, K. Sato2, K. Nagaoka2, H. Yukawa2, Y. Matsumoto3, T. Nambu4

1

University of Yamanashi, Kofu, Yamanashi, Japan, 2 Nagoya University, 3 National Institute of Technology, Oita
College, 4 National Institute of Technology, Suzuka College*
kaori.o@yamanashi.ac.jp (Kaori Omata)
Keywords : Membrane reactor, Hydrogen carrier, Ammonia decomposition, Hydrogen separation, Metal
membraneAmmonia, NH3, has recently attracted attention as one of the hydrogen
carriers. Producing hydrogen fuel from NH3 generally requires two steps:
breaking down NH3 into H2 and N2 and separating and purifying H2. This study
attempts to fabricate a membrane reactor for producing H2 directly from NH3 bycombining a V-10mol%Fe hydrogen permeable alloy membrane 1) and a
Ru/Cs2O/Pr6O11 catalyst2) for NH3 decomposition3).
A schematic illustration of a membrane reactor for H2 separation andpurification from NH3 is shown in Fig. 1. The membrane sample is sandwiched
between SUS316L gaskets and fixed using Swagelok VCR fittings as the sample
holder. 200 mg of the catalyst granules are set on the membrane sample andfixed with quartz wool. The sample holder is heated to 623 K using a tubularelectric furnace. The NH3 gas is fed to the catalyst from the outer tube of theinlet side at a flow rate of 10 or 20 mL min-1 and a pressure of 0.15-0.30 MPa
and decomposed to N2 and H2. The produced H2 is separated selectively throughthe membrane to the outlet side evacuated using a turbo-molecular pump.
The results of the NH3 decomposition using the membrane reactor are
shown in Fig. 2. The conversion for Ru/Cs2O/Pr6O11 catalyst alone, which is theresult of the SUS-316L plate instead of the V-10mol%Fe membrane, is also
Fig. 1. Schematic illustration
shown in the figure for comparison. While the NH 3 conversion for the catalystof the membrane reactor.
alone is 60% or less, combining the catalyst and V-10mol%Fe alloy membraneincreases the conversion to 80% or more. The hydrogenpoisoning for the catalyst or the reverse reaction is suppressed byremoving the H2 with the membrane during the NH3
decomposition, resulting in improved NH3 conversion. The
conversion tends to increase with increasing the reaction pressure
in contrast to the catalyst alone. The maximum conversion is
88.5% at 0.3 MPa. According to the H2 flow rate on the outlet
side, 89.4% of the H2 produced by NH3 decomposition ispermeated through the alloy membrane at this condition.
Therefore, the ratio of H2 separated directly to hydrogencontained in NH3 is calculated as 79% by multiplying 88.5% of
the NH3 conversion and 89.4% of the separated H2 ratio.
The Ru/Cs2O/Pr6O11 catalyst and the V-10mol%Fe alloy
membrane are highly durable, and the initial performance of theH2 production rate lasts for more than 3000 h. In addition, theproduced H2 gas conforms to ISO 14687e2:2019 Grade D for fuelFig. 2. Changes in NH3 conversion depending oncell vehicles because the NH3 and N2 concentrations are less than
total pressure with the membrane reactor.
0.1 and 100 ppm, respectively.
References
1) A. Suzuki, H. Yukawa, T. Nambu, Y. Matsumoto, Y. Murata, Int. J. Hydrog. Energy 42,22325-22329 (2017).
2) K. Nagaoka, T. Ebosh, N. Abe, S. Miyahara, K. Honda, K. Sato, Int. J. Hydrog. Energy 39, 20731-20735(2014).
3) K. Omata, K. Sato, K. Nagaoka, H. Yukawa, Y. Matsumoto, T. Nambu, Int. J. Hydrog. Energy 47, 8372-8381(2022).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-17 -B3-P204-18

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanThe effect of ball milling on hydrogen release property of TiH2
Mei Yuan1, Takahiro Kondo2,3*1Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8574, Japan.
Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan
3
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan*
takahiro@ims.tsukuba.ac.jp
Keywords: Titanium hydride, Ball milling, Hydrogen storage
2

Ti based compounds have been reported as excellent catalysts added into other metal hydrogen storage
materials to improve the property of release and uptake hydrogen1,2. TiH2 is one of the commonly used catalysts
that can significantly reduce the onset temperature of the material to release hydrogen3.Therefore, TiH2 is afascinating hydrogen storage material that deserves further discussion and research. However, regarding TiH2 asa catalyst, no definition or explicit elucidation of its mechanism has been achieved thus far. Meanwhile, ball
milling stands as the most commonly employed method for mechanically blending materials and enhancing theperformance of hydrogen storage materials. Hence, we conducted asystematic and fundamental study on the effect of ball milling on theperformance of TiH2, such as shape, size, material composition, andhydrogen release capabilities.
Firstly, as received TiH2 Powder was subjected to mechanicalmilling using a planetary ball milling at 400 rpm/min for 10min,
20min,30min, 1h, 2h and 4h. The ball to sample ratio was set to 75:1.
Then the ball milled powders were collected and stored in glove box. All
the sample handling was executed on glove box filled with high-purity
N2. Then all of samples were characterized by scanning electron
microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron
spectroscopy (XPS), thermogravimetry (TG), thermal desorption
spectroscopy (TDS) and so on.
The morphology and crystal size of ball-milled TiH2 with different
time of 10, 20, 30 min and 1, 2, 4 h were examined by SEM and XRDpeaks using Scherrer equation. As ball milling time increased, crystal
size and powder size were found to decrease significantly: crystal size
was decreased from 23.7 to 3.2 nm, for commercial TiH2 to 4 hball-milled TiH2.
Figure 1 hydrogen release property of different ball-milled sample
and commercial sample. A significant decrease in the onset temperatureof the first-step hydrogen release was found for ball-milled TiH2,
reducing from around 430 ℃ to approximately 150 ℃. While thetemperature for the principal hydrogen release in this step decreases
from 450 ℃ to around 280 ℃. However, with an increase in the ball
milling time above 1h, temperature for the principal hydrogen release in
the first step, from 280 ℃ to 320 ℃. On the other hand, the temperature
for the second-step hydrogen release continuously decreased from
510 ℃ to 400 ℃. The details mechanism of the change in H 2 releasetemperature will be discussed in the presentation.
In summary, systematic study has been presented for the effect ofdifferent ball milling time on the performance of TiH2. The results
suggest that ball milling produces smaller sized TiH2 enables to reduce
Fig. 1 TDS analysis of commercial
the first-step hydrogen release temperature about 150 ℃ and reduce theTiH2 and TiH2 ball -milled for 10, 20,
onset temperature as much as 280 ℃.
30 min and 1, 2, 4 h.
References:
1) Sandrock, G., Gross, K. & Thomas, G. Journal of Alloys and Compounds. 339, 299–308 (2002).
2) Peng, C., Yang, C. & Zhang, Q. J. Mater. Chem. A 10, 12409–12417 (2022).
3) Snider, J. L. et al. Int. J. Hydrogen Energy 47, 403–419 (2022).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-18 -B3-P204-19

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Hydrogen-gasochromic properties of Y-Mg, Ni-Mg, Mn-Mg and Gd
switchable mirror films
J. Wang1), T. Matsuno1), M. Kashiwagi1), I. Fabio2), T. Okajima1,2), Y. Oguchi3) and*
Y. Shigesato1)
1) Graduate school of Science and Engineering, Aoyama Gakuin University, Sagamihara 252-5258, Japan.
2) Aichi Synchrotron Radiation Center, Seto 489-0965, Japan.
3) Center for Instrumental Analysis, College of Science and Engineering, Aoyama Gakuin University,
Sagamihara 252-5258, Japan.
*Corresponding Author: yuzo@chem.aoyama.jp
Keywords: hydrogen-gasochromism, hydro-/dehydrogenation, Y-Mg, Ni-Mg, Mn-Mg, Gd
Recently, thermal control solid-state devices that mimic electric circuits have been attracting attentions [1-4].
The switchable mirror materials such as Y-Mg, Ni-Mg, Mn-Mg, Gd, etc., can be reversibly switched between
semiconductor (transparent) and metallic (reflective) states through hydrogenation and dehydrogenation
reactions, respectively [4-8]. However, it is characterized by its lack of memory property since it cannot maintainthe hydrogenated state unless hydrogen is continuously supplied. There are two methods of switching. One is thegasochromic method in which hydro-/dehydrogenation are performed directly by switching between hydrogengas and atmosphere, respectively [6-8], whereas the another is the electrochromic method in whichhydro-/dehydrogenation are performed by electrochemically driving hydrogen in the alkaline electrolyte [3].
Since the hydro-/dehydrogenation reactions of the switchable mirrors are reversible reactions, and as shownin previous studies, the thermal conductivity before and after hydrogenation is large, which could be expected tobe applied to thermal switches [4,7,8]. As for the basic understanding on these reactions, it should be quite
important to analyze on the temperature dependence of the reaction behavior. In this study, the gasochromic
method was adopted as the switching method. We deposited the 100 nm-thick Y-Mg and Ni-Mg alloy films
top-caped with a 5 nm-thick Pd film as catalyst by dc sputtering.
The in-situ analyses of optical and electrical properties were
performed under a mixture of 3% H2 and 97% N2 gases. The
hydro-/dehydrogenation kinetics of the gasochromic processes wereanalyzed in the temperature range from 30°C to 110°C (Fig. 1). In
the case of Ni-Mg, hydrogenation kinetics over a narrower
temperature range was analyzed. It was also found that oncehydrogenated at the certain high temperature and then hydrogenatedagain at room temperature (25°C), the hydrogenation properties
Fig. 1. The resistance changing rates of the
could not be restored [9]. The activation energies derived from
Ni-Mg and Y-Mg films at the various temperatures.
the temperature dependence of the hydro-/dehydrogenations
reaction rates for the Y-Mg film in the reversible
temperature range are shown in Fig. 2 (left) and (right),
respectively.
We would also like to analyze the temperaturedependence on the reactions of the other materials, such as
Mn-Mg or Gd films. The differences in the gasocromic
reactionsand
theiractivationenergies
forhydro-/dehydrogenation will be discussed in detail.
Fig. 2. Activation energies for hydrogenation (left) and dehydrogenation (right) reactions
for the Y-Mg films estimated by Arrhenius plots in the reversible temperature ranges.

References:[1] K. Kim, et al., Phys. Rev. B 94, (2016) 155203. [2] G. Wehmeyer, et al., Appl. Phys. Rev. 4 (2017) 041304.
[3] H. Kizuka, et al., Jpn. J. Appl. Phys., Vol. 54, No. 5, (2015) 053201. [4] H. Saito, et al., Proc. 40th Jpn. Symp.
Thermophys Prop. (2019) B223. [5] J. N. Huiberts, et al., Nature Vol. 380, No.6571, (1996) 231. [6]
H.Yoshimura, et al., Jpn. J. Appl. Phys. 45, (2006) 3479. [7] K. Sugimoto, et al., Proc. 42th Jpn. Symp.
Thermophys Prop. (2021) B312. [8] H. Yagi, et al., Proc. 42th Jpn. Symp. Thermophys. Prop. (2021) B313,(2022) B233. [9] K. Yoshimura, et al, Jpn. J. Appl. Phys. Vol. 46, No. 7A, pp. (2007) 4260.
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MRM2023/IUMRS-ICA2023

Fabrication of all-solid-state thin film thermal switches using hydro/dehydrogenation reactions of Y-Mg or Ni-Mg switching-mirror films
H. Ogiwara1), R.Nishimura1), M. Kashiwagi1), Y. Oguchi2), Y. Yamashita1,3), T. Yagi1,3), N.
Taketoshi1,3) and *Y. Shigesato1)
1)

Graduate school of Science and Engineering, Aoyama Gakuin University, Sagamihara 252-5258, Japan.
Center for Instrumental Analysis (CIA), College of Science and Engineering, Aoyama Gakuin University,
Sagamihara 252-5258, Japan.
3)
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology(AIST), Tsukuba 305-8563, Japan.
*Corresponding Author: yuzo@chem.aoyama.jp
Keywords: Y-Mg, Ni-Mg, all-solid-state thermal switches, hydro-/dehydrogenation, 3ω method2)All-solid-state thermal devices using laminated thin films are attracting attention as a variety of energy
efficiency technologies, such as the ability to use waste heat applications. The advantages of the all-solid-state
devices are that they can be switched using only laminated solid thin films. They should be also secureness,convenience and reliable because the electrolyte of “liquid-solution” is not used. The switchable mirror materials(SMMs) can reversibly change between semiconductor (transparent) state and metallic (mirror) state, which arecaused by hydro-/dehydrogenation, respectively [1]. We have been reporting on the large changes in thermal
conductivities of various SMM films depending on the changes in the electrical conductivity caused by hydro/dehydrogenation controlled by both gasochromic and electrochromic methods [2-6]. In this study we are focusing
on fabrication of the "all-solid-state thermal switches", in which the thermal conductivity can be largely controlled
by hydro-/dehydrogenations. All the 7 layers in the devises were deposited by magnetron sputtering, i.e.
transparent conducting film (ITO) / the switchable mirror films (Y-Mg or Ni-Mg) / catalyst film (Pd) / leakcurrent barrier film (thin-WO3) / ion (proton) conducting film (Ta2O5) / ion storage film (thick-WO3) / ITO on theglass substrate. The Pd layer is responsible for introducing and releasing hydrogen ions into the SMM layer andacts as a catalyst for hydro-/dehydrogenation reactions [2-6]. The ion-conducting layer Ta₂O₅ is an ion conductorthat does not allow electrons to pass through, whereas allows hydrogen ions to pass through. The ion storage layer,
WO3, acts as a counter electrode of the SMM films and to store the hydrogen ions. The separation layer of thethin-WO3 is to supress leakage current.
Figure 1 shows the schematic illustrations of the all-solid-state thermal switching devices [5]. The changes intransparency by applying ±5 V are shown in Fig. 2. Effective thermal conductivities of all the layers for the eachstates were analyzed quntitatively by the 3ω method. In the case of using the Y-Mg film, the effective thermal
conductivity for the dehydrogenated metalic state was 2.9 W m-1 K-1, whereas the one for the hydrogenated state
was 1.7 W m-1 K-1. The thermal conductivities for the devices using the Ni-Mg film instead of the Y-Mg film willbe also discussed in detail.
A part of this work was supported by JSPS Grants-in-Aid for Scientific Research (KAKENHI), Grant Number
23H01362.

Fig1. Schematic illustrations of the all-solid-state
thermal switching devices using the laminated films.

Fig2. The switching device using the Y-Mg filmin the metal or semiconductor states. 15 mm x 15 mm in size.

[1] Y. Yamada et al., Sol. Enegy Mater. Sol. Cells 99(2012) 73. [2] H. Yagi, et al., Proc. 42th Jpn. Symp.
Thermophys. Proc. Prop. (2021) B313, (2022) B233. [3] K. Sugimoto, et al., Proc. 42th and 43th Jpn. Symp.
Thermophys. Prop. (2021) B312 and (2022) B312. [4] H. Saito, et al., Proc. 40th Jpn. Symp. Thermophys. Prop.
(2019) B223. [5] R. Nishimura, et al., Proc. 43th Jpn. Symp. Thermophys. Proc. (2022) B313. [6] D. Murakami,
et al., Proc. 43th Jpn. Symp. Thermophys. Proc. (2022) B311.

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Thermal conductivity changes of electrochemically hydrogenated anddehydrogenated Pd-catalyzed Ni-Mg alloy thin film
D. Murakami1, Y. Yamashita1,2, T. Yagi1,2, M. Kashiwagi1, Y. Oguchi3, N. Taketoshi1,2, and*Y. Shigesato1
1 Graduate School of Science and Engineering, Aoyama Gakuin University, Sagamihara, 252-5258, Japan,
2 National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology(AIST), Tsukuba, 305-8563, Japan,
3 Center for Instrumental Analysis, College of Science and Engineering, Aoyama Gakuin University, Sagamihara,
252-5258, Japan,*yuzo@chem.aoyama.ac.jp
Keywords: thermal switching device, Ni-Mg alloy film, electrochemical hydrogenation/dehydrogenation, thermal
conductivity
Ni-Mg alloy films are known as the switchable mirror film not including rare earth elements. The switchable
mirror materials can be reversibly changed between semiconductor and metallic states by hydro- anddehydrogenation reactions, respectively.1) Since the free electron density is quite different between these two states,
the Ni-Mg alloy films are expected to be utilized for thermal switching devices in which thermal conductivity canbe controlled in the wide range.2) Saito et al. have reported that the thermal conductivity of the Y-Mg alloy thinfilm, the typical switchable mirror, can change between 7.1 W m-1 K-1 and 2.1 W m-1 K-1 by hydro- anddehydrogenation reactions.3) Since the electrical conductivity of Ni-Mg alloy is larger than those of Y-Mg alloy,
the better thermal switching characteristics for the Ni-Mg alloy is expected. In this study, the hydrogenated anddehydrogenated states of a Pd-caped Ni-Mg alloy film were electrochemically controlled and thermal
conductivities of both states were investigated using the in-situ rear-hearing/rear-detection type thermoreflectanceapparatus.
The Cr/Ni-Mg/Pd three-layered thin films were fabricated on unheated synthetic quartz glass substrates by dc
magnetron sputtering using Cr, Ni-Mg alloy (Mg: 84 at%), and Pd targets. Nominal thicknesses of the Cr, Ni-Mg,
and Pd films were 100 nm, 200 nm, and 5 nm, respectively. A pressure of Ar gas (99.999% in purity) during theNi-Mg sputter depositions was kept at 5.0 Pa. The Ni-Mg alloy and Pd were laminated without exposure to the air.
The Cr film plays roles of an electrode for electrochemical hydrogen intercalation and a reflective layer for the insitu thermoreflectance measurements. The thin Pd layer is a catalyst of the hydro-/dehydrogenations reactions. A
cyclic voltammetry (CV) using an electrochemical cell filedwith 1M KOH aqueous solution was performed for threecycles with a scan rate of 8 mVs -1 and a scanning range from
-1.2 V to 0 V for the sufficient hydrogenation of the Ni-Mg
As-deposition(spontaneous)alloy film after the thermal conductivity measurements in
Hydrogenation (-1.05 V)
the as-deposited state. Based on these electrochemical
Dehydrogenation (+0.3 V)
analyses, the hydrogenation and dehydrogenation potentials
were determined as -1.05 V and +0.3 V vs. Ag/AgCl,
respectively. After applying certain potentials, thermal
conductivities of the film at the hydro- and dehydrogenatedstates were measured.
Figure 1 shows the thermoreflectance signals of the NiMg alloy film in the as-deposited, hydro-, anddehydrogenated states. The thermoreflectance signals show
the clear difference between the hydro-/dehydrogenatedFig. 1. Thermoreflectance signals in the asstates. Furthermore, it is found that the thermoreflectancedeposited state, the hydrogenated state at -1.05
signal returns to almost the same as that in the as-deposited
V vs. Ag/AgCl and dehydrogenated state at +0.3
state if the hydrogen was removed from the Ni-Mg hydride
V for the Ni-Mg alloy film through the in-situ
film. The thermal conductivities and the other physicalmeasurement using 1M KOH aq.
properties will be reported in detail at the presentation.
Acknowledgements
A part of this work was supported by JSPS Grants-in-Aid for Scientific Research (KAKENHI), Grant Number
23H01362.
References
1) K. Yoshimura, J. Vac. Soc. Jpn. 57 (2014) 84 (in Japanese). 2) H. Yagi, et al., Proc. the 42nd Jpn. Symp.
Thermophys. Prop. (Online, October 25-27, 2021) B313 (in Japanese). 3) H. Saito, et al., Proc. of the 40th Japan
Symposium on Thermophys. Prop. (Nagasaki, October 28-30, 2019) B223 (in Japanese).
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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Reversible electrical and thermal conductivities change of Pd-catalyzed CoMg films by gasochromic hydrogenation using N2-H2(3 %) gas
K. Nakano1), Y. Yamashita1,2), T. Yagi1,2), M. Kashiwagi1), Y. Oguchi3), I. Fabio4),
T. Okajima1,4), N. Taketoshi1,2) and *Y. Shigesato1)
1)

Graduate school of Science and Engineering, Aoyama Gakuin University, Sagamihara 252-5258, Japan.
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science andTechnology (AIST), Tsukuba 305-8563, Japan.
3)
Center for Instrumental Analysis, College of Science and Engineering, Aoyama Gakuin University,
Sagamihara 252-5258, Japan.
4)
Aichi Synchrotron Radiation Center, Seto 489-0965 Japan.
*
Corresponding Author: yuzo@chem.aoyama.jp
Keywords: switchable mirror, Co-Mg alloy, thermal conductivity switch, hydro-/dehydrogenation, time domain
thermoreflectance method
2)

Thermoreflectance signal(phase), degree

Electrical Conductivity, S m-1

Co-Mg alloy is classified as one of the third-generation switchable
mirror materials that consist of magnesium and transition metals, such106
as Ni and Mn1). The Co-Mg alloy is considered to be mixtures of two
binary intermetallic compounds (hexagonal MgCo2 and cubic MgCo)2)
about 27 times
and hexagonal close-packed Mg. On the other hand, the Co-Mg alloy
105
hydride, that is semiconductor, consists of a mixture of rutile MgH2
and tetragonal Mg2CoH52). Since hydrogens leave the Co-Mg alloy
hydride in the air, the Co-Mg alloy in the dehydrogenated state has
104
as-depohydro.
dehydrsame chemical composition of the as-deposited state. This study aims.
o.
to clarify the thermal conductivity change of the Co-Mg alloy due toFig. 1. Electrical conductivity of the Co-Mg
alloy film in the as-deposited, hydrogenated,the hydro-/dehydrogenation reactions, i.e., metal-semiconductor
and dehydrogenated states.
transition, as expected as those of the Ni-Mg alloy3).
40
The Co-Mg alloy films with a nominal thickness of 200 nm were
deposited on the unheated quartz glass substrates by dc magnetron30
sputtering using a Co-Mg alloy target (Mg: 50 at%) and Mg pellets
with a total gas pressure of Ar of 3.0 Pa, followed by the deposition of20
the catalyst Pd films with a nominal thickness of 5 nm without
exposure to the air. For the thermal conductivity measurement10
specimen, a Mo transducer film was deposited before the deposition
0of the Co-Mg layer. The chemical composition of the Co-Mg alloy film
0
10
20
30
40
50
Delay time, ns
was analyzed to be Co : Mg = 28 : 72 by EPMA. The thermal
Fig. 2. Thermoreflectance signal of the Co-Mg
conductivities were measured using the in-situ rear heating/rearalloy film in the as-deposited, hydrogenated,
detection type picosecond pulsed light heating thermoreflectanceand dehydrogenated states.
apparatus. The all in-situ measurements were started after 1 hour
exposing the sample to the N2-H2(3 %) gas, whereas the measurements in the dehydrogenated state were carriedout after at least half an hour exposure to air again to remove all hydrogen. Figure 1 shows the electricalconductivity of the Co-Mg layer in each state. The electrical conductivity of the dehydrogenated state is about 27
times as large as that of the hydrogenated state. Figure 2 shows the thermoreflectance signals of the Pd/Co-Mg/Mo
layered film in each state. The signal in the hydrogenated state clearly differ from those of the others and the signal
in the dehydrogenated state corresponds to that in the as-deposited state. The thermal conductivities in thehydrogenated and dehydrogenated states are 0.9 W m-1 K-1 and 7.5 W m-1 K-1, respectively. Consequently, we
conclude that the electrical and thermophysical conductivities of Co-Mg alloy film change reversibly throughhydro-/dehydrogenation reactions. Structural analysis including XAFS will be shown in the poster presentation.
Acknowledgement
A part of this work was supported by JSPS Grants-in-Aid for Scientific Research (KAKENHI), Grant Number
23H01362.
References
1) Y. Kazuki et al., Synthesiology (in Japanese), Vol.5, No.4 (2012) 253.
2) van Geest-Lokhorst, A. C., Reflections on Switchable Mirror Devices, VRIJE University, 2006, Ph. D thesis.
3) H. Yagi, et al., Proceedings of the 43rd Japan Symposium on Thermophysical Properties (2022) B233.
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-22 -B3-P204-23

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Electrical, thermophysical and structural properties change for Gd
hydrides thin films controlled by gasochromic hydro-/dehydrogenation
R. Hirata1, Y. Yamashita1, 2, T. Yagi1, 2, M. Kashiwagi1, S. Takeya2, I. Fabio3, T. Okajima1, 3,
Y. Oguchi4, N. Taketoshi1, 2 and *Y. Shigesato1
1

Graduate School of Science & Engineering, Aoyama Gakuin University, Sagamihara 252-5258, Japan.
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science andTechnology (AIST), Tsukuba 305-8563, Japan.
3
Aichi Synchrotron Radiation Center, Seto 489-0965, Japan.
4Center for Instrumental Analysis, College of Science and Engineering, Aoyama Gakuin University,
Sagamihara 252-5258, Japan.
*
yuzo@chem.aoyama.ac.jp
Keywords: switchable mirror, gadolinium (Gd), gasochromism, hydrogenation, thermal switch
2

A thermal switch is a component of heat flow control technologies and has a sharp contrast in thermal
conductivity between two on-/off-states controlled by external fields [1] or chemical reactions [2, 3]. Sugimoto
et al. have focused on the switchable mirror materials which allows reversible switching between metal andsemiconductor using hydro-/dehydrogenation reactions and have reported the thermal conductivity contrast of
6.1 times for the Y-Mg hydrides thin film [3]. In this study, we focus on Gd hydrides [4] whose electricalconductivity contrast is expected to be much greater than that of Y-Mg hydride. The purposes of this study are todirectly fabricate GdH2 film to avoid the damage caused by the internal stresses due to a volume expansion of
7.4 % from Gd to GdH3 and to investigate the structural, electrical, and thermophysical properties of Gd and Gd
hydrides in the hydro-/dehydrogenated states.
The Pd/GdH2 (or Gd) /Mo films were fabricated by dc reactive magnetron sputtering under 1.0 Pa of a
mixture of Ar and H2 gases with the H2 flow ratios of 0, 5, 30, and 50 %. The nominal thicknesses of Pd, GdH2
(or Gd), and Mo are 5 nm, 300 nm, and 100 nm, respectively. The thermal conductivities of the films were
measured using an in-situ time-domain thermoreflectance apparatus. The Pd/GdH2 (or Gd) films were also
prepared under the same sputtering conditions for the in-situ electrical and structural properties analyses. The
measurements in the hydrogenated and dehydrogenated states were carried out after 90 min exposure to a
mixture of Ar and H2 (3 %) gases and after 90 min exposure to air, respectively. The measurement proceeded in
the order of the as-deposited, hydrogenated, and dehydrogenated states.
Figure 1 shows the XRD patterns of Pd/GdH2 (or Gd) films in the as-deposited state. Diffraction peaks of
GdH2 appear in all Pd/GdH2 samples in the as-deposited state, confirming that GdH2 films could be fabricateddirectly. Figure 2 shows the electrical conductivities of the Pd/GdH2 (or Gd) films in the as-deposited,hydrogenated, and dehydrogenated states. The electrical conductivities of all GdH2 films are smaller than thebulk value of 2.3×106 S·m-1 [5]. The contrast between the hydrogenated and dehydrogenated states for the
Pd/GdH2 film, 52 (5 %), 2 (30 %), and 46 (50 %) times, are smaller than that of 334 times for the Pd/Gd film.
Further results will be reported in the presentation.

Figure 1. XRD patterns of the Pd/GdH2 (or Gd) films with H2flow ratios of 0, 5, 30, and 50 % for the as-deposited state.

Figure 2. Electrical conductivities of the Pd/GdH2 (or Gd)
films with H2 flow ratios of 0, 5, 30 and 50 % for the
as-deposited, hydrogenated, and dehydrogenated states.

Acknowledgement
A part of this work was supported by JSPS Grants-in-Aid for Scientific Research, Grant Number 23H01362.
References
1) G. Wehmeyer et al., Appl. Phys. Rev., Vol. 4, 041304 (2017)., 2) H. Saito et al., Proc. Jpn. Symp. on
Thermophys. Prop., B223 (2019)., 3) K. Sugimoto et al., Proc. Jpn. Symp. on Thermophys. Prop., B312 (2022).,4) K. Yoshimura, J. Vac. Soc. Jpn., Vol. 57, No. 3, pp. 84-90 (2014)., 5) J. P. Burger et al., J. Less-Common Met.,
Vol. 103, pp. 381-388 (1984).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-23 -B3-P204-24

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Changes in electrical and thermal conductivities of Sm film by gasochromichydrogenation and dehydrogenation
M. Ueno1), Y. Yamashita1,2), T. Yagi1,2), M. Kashiwagi1), I. Fabio3), T. Okajima1,3), Y. Oguchi4), N.
Taketoshi1,2) and *Y. Shigesato1)
1) Graduate school of Science and Engineering, Aoyama Gakuin University, Sagamihara, 252-5258 Japan.
2) National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology(AIST), Tsukuba, 305-8563 Japan.
3) Aichi Synchrotron Radiation Center, Seto, 489-0965 Japan.
4) Center for Instrumental Analysis, College of Science and Engineering, Aoyama Gakuin University, Sagamihara,
252-5258, Japan.
*
Corresponding Author: yuzo@chem.aoyama.jp
Keywords: hydrogen gasochromism, switchable mirror, Samarium, hydrogenation/dehydrogenation, thermal switch
Recently, thermal switching devices that can switch between low and high thermal conductivities have attracted
attention [1], because of their effective use of waste heat energy for energy conservation. Kumar et al. have reported
on the changes in optical properties of the Sm films due to the electrochemical hydro-/dehydrogenation reactions [2].
A metallic SmH2 with a certain catalyst easily reacts on a dilute H2 gas to SmH3, which is a semiconductor andtransparent. The reverse reaction, from SmH3 to SmH2, also occurs under an ambient atmosphere. Such atransformation between metal and semiconductor is expected to cause a change in thermal conductivity due to thedifferent dominant heat carriers each other. In this study, in-situ analyses of the electrical and thermal conductivities
of a Sm film in the hydro-/dehydrogenated states were carried out by means of a gasochromic method.
The Sm film with a thickness of 200 nm was deposited on a 100 nm thick Mo film coated quartz glass substrateby dc magnetron sputtering using a Sm metal target (99.5 % in purity) at 1.0 Pa of an Ar gas. The surface of the Sm
film was capped with a Pd film with a nominal thickness of 5 nm by sputtering without exposure to the air. For thein-situ electrical conductivity measurement, a Sm single layer was also deposited on a quartz glass substrate under
the same sputtering conditions. The Sm films were exposed to a mixture of 3 % H2 and N2 gases for 1 hour tohydrogenate the film, whereas the hydrogenated films were exposed to the air for 1 hour to dehydrogenate the film.
Figure 1 shows the electrical conductivities of the Sm film in the as-deposited(Sm), hydrogenated(SmH3), anddehydrogenated(SmH2) state. The electrical conductivity for the hydrogenated state is about 200 times lower thanthat of the dehydrogenated state. Figure 2 shows the thermoreflectance signals of the Pd/Sm/Mo three-layer film forthe as-deposited state and 2 cycles of hydro-/dehydrogenated states. The thermoreflectance signals for thehydrogenated state decrease more slowly than those for the dehydrogenated state, which implies that thermal
conductivity changes due to the hydrogenation and dehydrogenation reactions. The difference between thethermoreflectance signals in the hydrogenated and dehydrogenated states in the 2nd cycle is smaller than that in the
1st cycle. The thermal conductivity of the Sm film in each state will be presented at the conference.
40
Thermoreflectancesignal(phase), degree

Electrical conductivity, S m-1

107

106

105

104

103

as-depo.
(Sm)hydrogenation dehydrogenation(SmH3)(SmH2)

Fig. 1. Electrical conductivities of the Sm film for each state.

30

20

10

0
0

10

20
30
40
50
Delay time, ns
Fig. 2. Thermoreflectance signals of the Pd/Sm/Mo
three-layer film for the as-deposited state and 2 cycles ofhydro-/dehydrogenated states.

Acknowledgement
A part of this work was supported by JSPS Grants-in-Aid for Scientific Research (KAKENHI), Grant Number
23H01362.
References[1] G. Wehmeyer et al, Appl. Phys. Rev. 4, 041304 (2017). [2] P. Kumar et al., Electrochem. Acta 49, 3355 (2004).

© The Materials Research Society of Japan (MRS-J)- B3-P204-24 -B3-P204-25

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanAbstract Guideline (Leave two lines for presentation number)

Development of Power Flow Simulation of Distributed Hydrogen Systemwith Transient Characteristics Enabling Cost Analysis and Control Study* Ryo Mitsui1 ,Yihuang Wang1 , Toshitaka Iwase1

1 Toyota Technical Development Corporation* ryo.mitsui@mail.toyota-td.jp

Keywords: Distributed Hydrogen System, Physical model, Simulation, EMS, Electrolysis
In recent years, the utilization of renewable energy, especially solar power, has been active from theperspective of both global energy issues and the transformation to decarbonized society. However, sincerenewable energy is greatly influenced by nature, the surplus power generated is a major issu e of its penetration.
Thus, Distributed Hydrogen Systems(DHSs) using water electrolys is cell (EC) to
keep the power balance, as shown in Fig. 1,
are attracting attention [1]. DHSs enableenergy time-shift by storing surplus powerfrom renewable energy sources as hydrogen.
However, the high cost of EC as well as its
auxiliary equipment, and complex system
control, such as coordinating a huge amountof modules and stacks while limiting thenumber of startups and shutdowns due to theenlargement of DHSs, are challenges fortheir introduction.
In this study, a multi-domain power-flow
DHS simulator has been developed in
MATLAB/Simulink, which enables cost
analysis and control studies (Fig. 2).
Fig. 1. A Distributed Hydrogen System (DHS) proposed by RIKEN.
Meanwhile, for EC, a key technology todecarbonized society, a physical model withovervoltage separation has been developed torepresent transient characteristics under
different temperature [2, 3].
With the cooperation of RIKEN, thisstudy compared simulation result with real
Small PV changes
data from RIKEN’s DHS, confirming that it
absorbed by battery
is possible to reproduce the qualitative
behavior of transient characteristics at
multiple temperature levels of the entire
system. It is also confirmed that accurate cost
analysis is possible by conducting 1-year
simulation with solar radiation data within
Rapid changes absorbed by battery (faster) and EC (slower)
Japan.
7:00
10:00
13:00
16:00
By simulating the transient behavior of
multiple devices, this model enables system
Fig. 2. 1-day simulation showing transient behavior of the DHS with
control studies for DHSs. Also, it is expected
photovoltaics (PV).
to be put to practical use for studies such as
the energy power storage with Business Continuity Plan considered and energy management working to keep thepower balance.
References:
1) D. Yamashita, K. Tsuno, K. Koike, K. Fujii, S. Wada, M. Sugiyama, Int. J. Hydrog. Energy, 44, 27542-27552(2019).
2) Z. Abdin, C.J. Webb, E.MacA. Gray, Int. J. Hydrog. Energy, 40, 13243-13257 (2015).
3) V. Liso, G. Savoia, S.S. Araya, G. Cinti, S.K. Kær, Energies, 11, 3273 (2018).

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-25 -B3-P204-26

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Zinc Aqueous Battery Anode Coated with Zinc Ion Conductive Polymer for
Suppression of Dendrite Growth and Inhibition of Irreversible Hydrogen
Evolution Reaction*

Dae Yeop Jeong1, Won Il Park*

1

Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, Republic of Korea
wipark@hanyang.ac.kr
Keywords : Zinc ion battery, Zn metal anode, protective layer, PMMA*

Zinc aqueous ion batteries offer significant advantages in terms of their low cost, high theoretical capacity,and recyclability. However, the cyclic performance of these batteries is hampered by challenges related todendrite growth and irreversible hydrogen evolution reactions occurring at the zinc metal anodes and in the
aqueous electrolyte. [1, 2] In this study, we propose an approach to address these challenges by introducing aprotective layer composed of a zinc salt-added polymethylmethacrylate (PMMA:Zn) on the anode surface. The
PMMA:Zn layer effectively mitigates direct contact between the electrode and electrolyte, thereby suppressing
the undesired hydrogen evolution reaction. Moreover, the incorporation of uniformly dispersed zinc salts within
the PMMA layer enhances ion conduction across the protective coating, promoting uniform zinc deposition
between the current collector and the PMMA:Zn layer. As a result, this simple PMMA:Zn coating demonstrates
remarkable improvements in cyclic performance, achieving a high Coulomb efficiency of nearly 100% forextended periods exceeding 2,000 hours, and enabling stable operation even at high current densities of 10 mA
cm-2.

References
1) T. Wang, C. Li, X. Xie, B. Lu, Z. He, S. Liang, J. Zhou, ACS Nano 2020, 14, 12, 16321–16347.
2) L. E. Blanc, D. Kundu, L. F. Nazar, Joule 4, 771–799, April15, 2020

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-P204-26 -MRM2023/IUMRS-ICA2023

Oral Session | B. Energy | [B-3] Hydrogenomics[B3-O301] Oral 301
Chair:Toyoto Sato (Shibaura Institute of Technology)
Wed. Dec 13, 2023 10:00 AM - 12:00 PM Session 14 (Room J)[B3-O301-01 (Symposium Invited)] A “ Data-Theory-Methodology-Experiment”
Framework to Design Effective Materials for
Hydrogen Generation and Utilization*Hao Li1 （1. Tohoku Univ. (Japan)）
10:00 AM - 10:30 AM[B3-O301-02]

Boron monosulfide as an electrocatalyst for theoxygen evolution reaction*Linghui Li1, Satoshi Hagiwara2, Cheng Jiang3, Haruki Kusaka1,
Norinobu Watanabe1, Takeshi Fujita4, Fumiaki Kuroda2,
Akiyasu Yamamoto5, Masashi Miyakawa6, Takashi Taniguchi6,
Hideo Hosono7,6, Minoru Otani2, Takahiro Kondo8,9 （1.
Graduate School of Pure and Applied Sci., Univ. of Tsukuba,
Tsukuba (Japan), 2. Center for Computational Sci., Univ. of
Tsukuba, Tsukuba (Japan), 3. Inst. of Technical andMacromolecular Chemistry, RWTH Aachen Univ., Aachen(Germany), 4. School of Environmental Sci. and Engineering,
Kochi Univ. of Tech., Kochi (Japan), 5. Tokyo Univ. ofAgriculture and Tech., Tokyo (Japan), 6. Res. Center for
Functional Materials, NIMS, Tsukuba (Japan), 7. Materials Res.
Center for Element Strategy, Tokyo Inst. of Tech., Yokohama(Japan), 8. Department of Materials Sci. and Tsukuba Res.
Center for Energy Materials Science, Inst. of Pure and AppliedSci., Univ. of Tsukuba, Tsukuba (Japan), 9. Advanced Inst. forMaterials Res., Tohoku Univ., Sendai (Japan)）
10:30 AM - 10:50 AM[B3-O301-03]

Reducing H2 Release Temperature From MgH2
Using Ni/HB Nanocomposite*Natsumi Noguchi1, Kazuho Goto1, Shin-ichi Ito1, Takeshi Fujita
2, Hideo Hosono3,4, Shin-ichi Orimo5,6, Takahiro Kondo5,7,8 （1.

Univ. Tsukuba (Japan), 2. Kochi Univ. Tech. (Japan), 3. Tokyo
Tech. (Japan), 4. NIMS (Japan), 5. WPI-AIMR, Tohoku Univ.
(Japan), 6. IMR, Tohoku Univ. (Japan), 7. TREMS, Univ. Tsukuba(Japan), 8. ZeroEFM, Univ. Tsukuba (Japan)）
10:50 AM - 11:10 AM[B3-O301-05]

Ammonia Electrolysis Using Ni2P@N-C
Electrocatalyst for Eco-friendly Hydrogen
Production*Chanmin Jo1, Subramani Surendran1, Min-Cheol Kim2,
Gnanaprakasam Janani 1, Dae Jun Moon 1,3, Joon Young Kim1,3, Jung Kyu Kim2, Uk Sim1,3 （1. Korea Inst. of Energy Tech.

©The Materials Research Society of JapanMRM2023/IUMRS-ICA2023(Korea), 2. Sungkyunkwan Univ. (Korea), 3. NEEL Sci., INC.
(Korea)）11:30 AM - 11:50 AM©The Materials Research Society of Japan

B3-O301-01 (Symposium Invited)

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan[Abstract Guideline (Leave two lines for presentation number)]

A “Data-Theory-Methodology-Experiment” Framework to Design Effective
Materials for Hydrogen Generation and Utilization*
1

Hao Li1

Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan
li.hao.b8@tohoku.ac.jp
Keywords: Materials Theory, Materials Design, Electrocatalyst, Electrolyte, Hydrogen Storage*

The design of solid-state materials for hydrogen generation and utilization is essential for a sustainable future.
However, conventional materials search sometimes relies on the trial-and-error process from experiments.
Meanwhile, theoretical analysis of materials is sometimes too complicated to develop a clear guideline forexperiments. This talk will discuss an avenue to realize a data-driven framework for hydrogen-related materials
design combining data-mining, materials theory, computational methodology development, and experiments. In
particular, we will discuss i) how to reduce the complexity in catalyst design by materials theory and ii) how todevelop new computational methods (i.e., new package, model, and algorithm) to accelerate materials simulation.
This talk will show the predictive power of theory in electrochemical and thermal catalysis,1-3 solid-state hydride
electrolytes, and solid-state hydrogen storage materials.4-5 We will also discuss the successful design of an“electron-refinery” strategy by transforming high-temperature thermal catalysis into low-temperatureelectrocatalysis.6 Finally, we will discuss the practical design of materials combining data science, materials
theory, computational screening, computational methodology development, and experiments.
References:
1) H. Li, S. Kelly, D. Guevarrac, Z. Wang, Y. Wang, J. A. Haber, M. Anand, G. Gunasooriya, C. S. Abraham, S.
Vijay, J. M. Gregoire, J. K. Nørskov. Nature Catal. 4, 463-468 (2021)
2) M. Li, X, Wang, K. Liu, H. Sun, K. Huang, D. Sun, Y. Tang, W. Xing, H. Li, G. Fu, Adv. Mater. 2302462(2023)
3) C. Liu, Z. Yu, F. She, J. Chen, F. Liu, J. Qu, J. M. Cairney, C. Wu, K. Liu, W. Yang, H. Zheng, Y. Chen, H.
Li, L. Wei, Energy Environ. Sci. 16, 446-459 (2023)
4) S. Dong, C. Li, J. Wang, H. Liu, Z. Ding, Z. Gao, W. Yang, W. Lv, L. Wei, Y. Wu, H. Li, J. Mater. Chem. A,
10, 22363-22372 (2022).
5) S. Dong, C. Lia, E. Lv, J. Wang, H. Liu, Z. Gao, Z. Ding, W. Xiong, W. Yang, H. Li, J. Mater. Chem. A, 10,19839-19851 (2022).
6) H. Li, C. S. Abraham, M. Anand, A. Cao, J. K. Nørskov, J. Phys. Chem. Lett., 13, 9, 2057–2063 (2022)

MRS-Japan© The Materials Research Society of Japan (MRS-J) - B3-O301-01 (Symposium Invited) -B3-O301-02

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Boron monosulfide as an electrocatalyst for the oxygen evolution reaction
Linghui Li1, Satoshi Hagiwara2, Cheng Jiang3, Haruki Kusaka1, Norinobu Watanabe1, Takeshi
Fujita4, Fumiaki Kuroda2, Akiyasu Yamamoto5, Masashi Miyakawa 6, Takashi Taniguchi6,
Hideo Hosono6,7, Minoru Otani2, *Takahiro Kondo8,9
1 Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan
2 Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
3 Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen 52074, Germany
4 School of Environmental Science and Engineering, Kochi University of Technology, Kochi 782-8502, Japan
5 Tokyo University of Agriculture and Technology, Tokyo 1838538, Japan
6 Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
7 Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503, Japan
8 Department of Materials Science and Tsukuba Research Center for Energy Materials Science, Institute of Pureand Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan
9 Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan* takahiro@ims.tsukuba.ac.jp

Keywords : boron monosulfide, electrocatalyst, oxygen evolution reaction, renewable energy device
As a clean and reliable energy technology, hydrogen is regarded as an appropriate alternative to fossil fuel,while water electrolysis using intermittent electric energy represents a promising commercial technology forindustrial hydrogen production [1]. Water splitting reaction consists of hydrogen evolution reaction (HER) at thecathode and oxygen evolution reaction (OER) at the anode. Compared with the HER, the OER has sluggish
kinetics and a large reaction barrier, limiting the efficiency of electrocatalytic water splitting [2]. Thus, thedevelopment of highly active oxygen evolution electrocatalysts has become aresearch hotspot. Currently, noble metals and metal oxides are the mostwidely used catalysts for OER electrocatalysis. However, metal-based
catalysts often suffer from multiple disadvantages, including high cost, lowselectivity, poor durability, impurity poisoning and fuel crossover effects [3].
Therefore, metal-free catalysts have received increasing interest as promising
electrocatalysts for advanced energy conversion and storage.
We focused on rhombohedral boron monosulfide (r-BS), which is a newmetal-free catalyst. r-BS was synthesized by a previously reported
high-pressure solid-state reaction [4], wherein a mixture of amorphous boronand sulfur with an atomic ratio of 1:1. Here, we report that r-BS mixed withgraphene (r-BS+G) as a new metal-free electrocatalyst, shows promising
electrocatalytic activity with much better performance than most publishedmetal-based catalysts in 1M KOH solution [5].
To prepare the r-BS+G mixture, r-BS powder and GNP were combined inethanol and then exposed to bath sonication. As shown in Fig. 1a and 1b, ther-BS+G shows significantly enhanced OER activity with the ultralow an
overpotential of 259 mV at 10 mA cm −2, which is 41 mV better thancommercial RuO2. Furthermore, the overpotential (259 mV) of r-BS+G ismuch lower than those of most reported metal-free OER electrocatalysts [6].
Fig. 1 a, Linear sweep voltammetry curves toward
The mixing process was just a simple sonication but probably ameliorated the
OER. b, Linear sweep voltammetry curves ofconductivity to effectively used active sites of r-BS. And the stability of r-BS
r-BS+G after 500 CV cycles (1.20 V-1.53 V) [5].
was explored by cyclic voltammetry (CV), as Fig. 1b exhibited, after CV
between 1.20 and 1.53 V (v s. RHE) for 500 cycles, r-BS+G showed
negligible degradation, demonstrating its good durability.
In summary, we have developed a new effective metal-free electrocatalyst for OER, and it gives a new
strategy to study high-efficient electrocatalysts for future potential applications.
References:1) Z. Y.Yu, Y. Duan, et al. Adv. Mater. 33, e2007100 (2021).
2) P. Zhai, C.Wang, et al. Nat. Commun. 14, 1873 (2023).
3) S. Pan, H. Li, D. Liu, et al. Nat. Commu. 13, 1-10 (2022).
4) H. Kusaka, et al., J. Mater. Chem. A, 9, 24631 (2021).
5) Li. L, et al., Submitted.
6) Z. P. Wu, et al., Adv. Fun. Mater. 30, 1910274 (2020).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O301-02 -B3-O301-03

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Reducing H2 Release Temperature From MgH2 Using Ni/HB Nanocomposite*

N. Noguchi1, K. Goto1, S. Ito2, T. Fujita3, H. Hosono4,5, S. Orimo6,7, and T. Kondo2,6,8*

1

Graduate School of Pure and Applied Sciences, University of Tsukuba, 2Department of Materials Science andTsukuba Research Center for Energy Materials Science, Institute of Pure and Applied Sciences, University ofTsukuba, 3School of Environmental Science and Engineering, Kochi University of Technology, 4Materials
Research Center for Element Strategy, Tokyo Institute of Technology, 5Research Center for Material
Nanoarchitectonics, National Institute for Material Science, 6The Advanced Institute for Materials Research (WPIAIMR), Tohoku University, 7Institute for Materials Research (IMR), Tohoku University, 8Tsukuba ResearchCenter for Energy Materials Science (TREMS), Institute of Pure and Applied Sciences, and R&D Center for Zero
CO2 Emission Functional Materials, University of Tsukuba*
takahiro@ims.tsukuba.ac.jp (T.K.)
Keywords : HB sheets, Ni nanocluster, Hydrogen storage material, 2D material, Nano-composites
Hydrogen boride (HB) sheets are two-dimensional materials comprising a negatively charged hexagonalboron network and positively charged hydrogen atoms with a stoichiometric ratio of 1:1.1 In a previous study, it
was reported that HB sheets reduce metals with redox potentials higher than Ni to form metal nanocomposites.2
We reported the spontaneous formation of highly dispersed Ni nanoclusters on HB sheets.3 The product is called
Ni/HB composite. The spontaneous reduction of Ni ions by the HB sheet was monitored by in situ measurementswith a UV-visible spectrometer. Considering the increase in absorbance over time, the results suggest that Ni metalclusters were growing on the HB sheet. Based on the results of transmission electron microscopy, X-ray
photoelectron spectroscopy, X-ray diffraction, and selected area electron diffraction, Ni nanoclusters were
spontaneously formed on the HB sheet, small (1-3 nm in diameter) and randomly distributed (Fig. 1) 3.
Mg-based alloys, including MgH2, are attracting attention4 as hydrogen storage materials because Mg isabundant on earth, they are lighter in weight than other alloy-based materials, have a high gravimetric hydrogendensity (up to 7.6 wt%), and can be safely transported due to their thermodynamic stability (ΔH = -74.5 kJ/mol).
However, hydrogen release and absorption are slow due to the strong bonding between Mg and hydrogen, and theamount of hydrogen absorbed decreases with repeated absorption and desorption. In addition, MgH2 isthermodynamically stable and thus safe, but requires high temperatures for hydrogen release. Therefore, a
reduction in temperature and an increase in the rate of hydrogen absorption and release are required for practicaluse. To solve these problems, supporting finely processed MgH2 on two-dimensional materials with catalysts has
been widely used4,5. In particular, the use of Ni as a metal catalyst has been reported to increase hydrogen
absorption and lower hydrogen release and absorption temperatures6. Herein, we will report that MgH2 supportedon Ni/HB composite (MgH2-Ni/HB) shows lower H2 release temperature. We hypothesized that by loading MgH2
onto Ni/HB, the aggregation of MgH2 would be prevented and the catalytic effect of Ni would lower the H2 releasetemperature. Practically, the H2 release temperature of
MgH2-Ni/HB was 567 K, about 130 K lower than that ofcommercial MgH2 (700 K) (Fig. 2). It is also interesting tonote that the shape of the hydrogen intensity peak remained
unchanged as a single peak. If only the MgH2 in the Ni
contact area were affected, there would be MgH2 withdifferent compositions and the peak would be split into two
or more. Thus, this result suggests that 2wt% Ni affects theentire MgH2, not just the Ni-MgH2 contact area. Therefore,
Fig. 1 TEM image of Ni/HB composite, and
it is possible that Ni acts as a catalyst, lowering the activation
histogram of diameter of Ni nanoclusters3.
energy, or a new compound is formed from Ni, HB, and
MgH2, raising the energy of the reactants and lowering theapparent activation energy. The details of the results
including thermodynamic parameters measurements will bepresented.
References :1) Nishino, H. et al. J. Am. Chem. Soc. 139, 13761 (2017).
2) Ito, S. I. et al., Chem. Lett. 49, 789 (2020).
3) Noguchi, N. et al., Molecules 27, 8261 (2022).
4) L. Ren, et al., Nano-Micro Lett. 14, 144 (2022)
5) C. Duan, et al., Renewable Energy. 187, 417 (2022)
Fig. 2 H2 release during heating.
6) Dan, et al., ACS Appl. Energy Mater. 5, 4976 (2022)
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O301-03 -B3-O301-05

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Ammonia Electrolysis Using Ni2P@N-C Electrocatalyst for Eco-friendly
Hydrogen Production
Chanmin Jo1, Subramani Surendran1, Min-Cheol Kim2, Gnanaprakasam Janani1, Dae Jun
Moon1,3, Joon Young Kim1,3, Jung Kyu Kim2 and *Uk Sim1,3
1

Hydrogen Energy Technology Laboratory, Korea Institute of Energy Technology (KENTECH), 200
Hyeoksin-ro, Naju, Jeonnam 58330, Republic of Korea, 2 School of Chemical Engineering, Sungkyunkwan
University, 2066 Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea, 3 Research Institute, NEEL Sciences,
INC., 58326 Jeollanamdo, Republic of Korea*
usim@kentech.ac.kr (Uk Sim)
Keywords : Ammonia electrolysis, Ammonia Oxidation, Nickel phosphide, Hydrogen carrier, Hydrogenproduction
Hydrogen, an alternative energy source, is emerging torealize carbon neutrality through substitution of fossil fuels.
There is a need to improve transportation efficiency by usinghydrogen carriers instead of hydrogen, which has limitations
in transportation. Ammonia is a promising material for use asa hydrogen carrier. Such ammonia can be converted intohydrogen through ammonia electrolysis, and theoretically,energy consumption is low and COx is not generated.
Ammonia electrolysis is carried out through an oxidation
reaction (AOR) at the anode and a hydrogen generation
reaction (HER) at the cathode. Non-noble metal catalysts,
which are catalytic materials to replace noble metals such as
Pt, are being studied. Among them, nickel is a material withexcellent AOR activity, but it has a corrosion problem. To
solve this problem, it was synthesized in the form of aphosphide known to have good corrosion resistance.
In this work, nickel phosphide (Ni2P@N-C) supported on
nitrogen-doped carbon for ammonia electrolysis was
synthesized by hydrothermal method. To determine whether
AOR or not, a three-electrode system was constructed tomeasure the ammonia concentration profile. based on theelectrical conductivity and charge dynamics of the catalyst
improved by the formation of the N-doped carbon matrix,
about 78% of the ammonia decomposition was confirmed
compared to the initial concentration. In the whole cellsystem, 11.2 mL of hydrogen generated during 30 minutes
was captured. Ammonia electrolysis shows improvedhydrogen production over water electrolysis.

Fig. 1. H2 generation of Ni2P@N-C with and without
NH4OH

References :1) C Jo, S. Surendran, M.-C. Kim, T.-Y. An, Y. Lim, H. Choi, G. Janani, S. C. Jesudass, D. J. Moon, J. Kim, J.
Y. Kim, C. H. Choi, M. Kim, J. K. Kim, and U. Sim, Chem. Eng. J. 463, 142314 (2023).

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O301-05 -MRM2023/IUMRS-ICA2023

Oral Session | B. Energy | [B-3] Hydrogenomics[B3-O401] Oral 401
Chair: Takahiro Kondo (University of Tsukuba),Takahiro Ishikawa (The University of Tokyo)
Thu. Dec 14, 2023 9:00 AM - 12:00 PM Session 14 (Room J)[B3-O401-01]

Topological Data Analysis Based on Persistent
Homology for the Superionic Conductors*Ryuhei Sato1, Kazuto Akagi1, Shigeyuki Takagi2, Kartik Sau1,3,Kazuaki Kisu2, Hao Li1, Shinichi Orimo1,2 （1. Advanced
Insitute for Materials Research, Tohoku University (Japan), 2.
Institute for Materials Research, Tohoku University (Japan), 3.
Mathematics for Advanced Materials Open Innovation
Laboratory, National Institute of Advanced Industrial Scienceand Technology (Japan)）
9:00 AM - 9:20 AM[B3-O401-02]

A Comprehensive Study of Correlation Effects
on Ion Conduction in Hydrides*Kartik Sau1,2, Shigeyuki Takagi3, Tamio Ikeshoji2, Kazuaki Kisu3, Ryuhei Sato1, Shin-ichi Orimo1,2 （1. Advanced Institute forMaterials Research (WPI-AIMR), Tohoku University (Japan), 2.
Mathematics for Advanced Materials Open Innovation
Laboratory (MathAM-OIL), AIST, c/o WPI-AIMR, Tohoku
University, Sendai 980-8577, Japan (Japan), 3. Institute forMaterials Research (IMR), Tohoku University, Sendai 9808577, Japan (Japan)）
9:20 AM - 9:40 AM[B3-O401-03]

Evolutionary Search for Superconducting
Phases in the Lanthanum-Nitrogen-Hydrogen
System with Universal Neural Network Potential
PFP*Takahiro Ishikawa1, Shinji Tsuneyuki1 （1. The Univ. of Tokyo(Japan)）9:40 AM - 10:00 AM[B3-O401-04 (Symposium Invited)] Development of High-pressure Diffusion Control
Method for Synthesizing Metastable Materials*Masaya Fujioka1,2 （1. Advanced Industrial Science andTechnology (Japan), 2. Hokkaido Univ. (Japan)）
10:20 AM - 10:50 AM[B3-O401-05]

Synthesis of Complex Transition Metal Hydrides
Containing Polynuclear Hydride Complexes withHigh Hydrogen Coordination*Shigeyuki Takagi1, Takehiro Hashimoto1, Kenjiro Otsuki1,
Reina Utsumi2,3, Yuki Nakahira2, Hiroyuki Saitoh2,3, Shin-ichi
Orimo1,4 （1. Institute for Materials Research, Tohoku
University (Japan), 2. National Institutes for Quantum Science©The Materials Research Society of JapanMRM2023/IUMRS-ICA2023

and Technology (Japan), 3. University of Hyogo (Japan), 4.
Advanced Institute for Materials Research, Tohoku University(Japan)）
10:50 AM - 11:10 AM[B3-O401-06]

Mn-rich Al– Mn alloy hydrides synthesizedunder high pressure and high temperature withthe aid of in-situ synchrotron radiation X-ray
diffraction measurement*Reina Utsumi1,2, Saya Ajito3, Yuki Nakahira1, Hiroyuki Saitoh1,2, Tetsu Watanuki1,2, Toyoto Sato4, Shigeyuki Takagi3, Eiji
Akiyama3, Shin-ichi Orimo3 （1. National Inst. for Quantum Sci.
and Tech. (Japan), 2. Univ. of Hyogo (Japan), 3. Tohoku Univ.
(Japan), 4. Shibaura Inst. Tech. (Japan)）
11:10 AM - 11:30 AM[B3-O401-07]

High-pressure and high-temperature synthesisof novel hydrides with the aid of in-situ
synchrotron radiation x-ray diffraction
measurement*Hiroyuki Saitoh1 （1. National Institutes for Quantum Scienceand Technology (Japan)）
11:30 AM - 11:50 AM©The Materials Research Society of Japan

B3-O401-01

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Topological Data Analysis Based on Persistent Homology for the Superionic
Conductors*

Ryuhei Sato 1, Kazuto Akagi1, Shigeyuki Takagi2, Kartik Sau1,3, Kazuaki Kisu2, Hao Li1,
Shin-ichi Orimo1,2
1Advanced Institute for Materials Research, Tohoku University, 2Institute for Materials Research, Tohoku
University, 3Mathematics for Advanced Materials Open Innovation Laboratory, National Institute of Advanced
Industrial Science and Technology*
ryuhei.sato.c1@tohoku.ac.jp
Keywords: Topological data analysis, Persistent homology, Superionic conductor, concerted motion
There is a common phenomenon in hydride-based superionic conductors such as LiCB9H101 and Ba-Li
oxyhydrides2 called the concerted motion of ions. In this concerted motion of ions, multiple ions migrate
simultaneously. In this phenomenon, the interaction between mobile ions and the interaction between the mobile
ion and the lattice (or complex hydrides) must be taken into account. In other words, the concerted motion ofions is a complex many-body problem. Therefore, it is difficult to understand such phenomena fromconventional two-body correlation functions or macroscopic properties of the entire system.
Topological data analysis based on persistent homology is a method to analyze a pore or ring structurecomposed of atoms in a given atomic coordinate. The persistence diagram obtained from this analysis is a
distribution of the obtained ring structure and the ring structure composed of multiple atoms can be easily
converted into two-dimensional information. Considering the conventional picture in defect chemistry, ion
migration occurs around ionic defects. Ionic defects can be analyzed as large ring or pore structures on thepersistence diagram. Therefore, it is considered that ion migration can be analyzed from the changes in this ring
structure related to the ionic defect during ion migration. Here, we performed topological data analysis on
molecular dynamics simulations of superionic conductors to clarify whether such a persistent diagram isapplicable to the analysis of complex ion migration like concerted motion of ions3.
The figure shows the time-averaged persistence diagram of α-AgI (a known solid-state superionic conductor)
during 3-ns NVT molecular dynamics simulations. AgI shows a phase transition around 440 K and α-phaseshows high conductivity. In this calculation, only the α-phase is obtained because the cell size is fixed for that of
α-phase, but superionic conduction is observed in the temperature range above 440K. Comparison of thepersistence diagrams shows that a new ring
structure (black dotted line) appears withsuperionic conduction. Therefore, these
new ring structures are considered to berelated to the ion migration. We obtained
statistics on the shape of the ring structure,such as the number of ions and the distance
between ions, and determined the averaged
structure for each (Birth,Death) mesh.
Based on the obtained statistics, the newring structures along the black dotted line
are four-membered rings. The concerted
motion of Ag ions via the four-memberedring is reproduced by deforming thefour-membered ring along the dotted line,
as shown in Fig (b), showing us that
topological data analysis is effective forcomplex ion migration like concerted
motion of ions.
References : 1) S. Kim et al. Nat.
Figure (a) Time-averaged persistence diagram of theCommun., 10 (2019) 1081. 2) F. Takeiri et.
ring structure during MD simulations of α-AgI at 360
al., Nat. Mater., 21 (2022) 325. 3) R.
and
1000K. (b) Ag migration via four-membered ring
Sato et al., J. Chem. Phys., 158 (2023)
reproduced
from the reverse analysis of persistence
144116.
diagram3.
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O401-01 -B3-O401-02

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Investigating Correlation Effects on Cationic Conduction in Hydrides: A
Comprehensive Study*Kartik Sau,1, 2, Shigeyuki Takagi,3 Tamio Ikeshoji,2 Kazuaki Kisu,3 Ryuhei Sato,1 and Shin-ichi Orimo1, 3
1Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Aoba-ku, Sendai 980-8577, Japan
Mathematics for Advanced Materials Open Innovation Laboratory (MathAM-OIL), AIST, c/o WPI-AIMR,
Tohoku University, Sendai 980-8577, Japan
3
Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577, Japan*
kartik.sau.d2@tohoku.ac.jp
Keywords: Molecular dynamics simulation, Ion conduction, Ion-ion correlation
2

Complex metal hydrides have received significant attention as potential solid electrolytes in all-solid-statebatteries [1, 2]. Their remarkable ionic conductivity in the high-temperature phase makes them suitable candidates
for such applications. However, their conductivity at room temperature is considerably low, and achieving a highconducting phase at low temperatures presents a challenge that has attracted substantial research interest. Despite
recent efforts to understand the origin and factors influencing high ionic conductivity at high temperatures, many
aspects remain elusive. In this study, we aim to shed light on the role of cation-cation, anion-cation, and anionanion correlations (Figure 1) in cationic conduction by employing molecular dynamics (MD) simulations.
Specifically, we will focus on Li2B12H12, LiCB11H12, and C2B10H12 and utilize a previously established force-field.

Figure 1. (a) Ball and stick model of Ordered structure of Li2B12H12. Schematic diagram of (b) cation-cation, (c)anion-cation (paddlewheel mechanism), and (d) anion-anion correlation. Where the red, green, and blue balls are
Li, B, and H, respectively and the blue arrow indicates the translational or diffusional motion.
The previously developed force-field has successfully demonstrated the ordered-disordered phasetransition, as well as the structural and dynamical behavior of this series of complex hydrides [3, 4]. By conducting
comparative MD simulations on these materials, we can gain insights into the relationship between cation-cation,
anion-cation, and anion-anion correlations.Furthermore, we can analyze the correlation study by altering theanionic ordering, specifically between body-centered or face-centered positions. Understanding how such changes
in anionic ordering affects the transition temperature of the ordered-disordered phase transition is crucial for
lowering the transition temperature.
In summary, this study aims to elucidate the influence of cation-cation, anion-cation, and anion-anion
correlations on cationic conduction in complex hydrides. By utilizing MD simulations and a well-establishedforce-field, we can gain valuable insights into the behavior of these materials and their potential for improving theperformance of all-solid-state batteries.
References: [1] Mohtadi and Orimo, Nat. Rev. Mater. (2017). [2] Kim et al., Nat. Commun. (2019).
al., Chem. Mater. (2021). [4] Sau et al., Mater. Adv. (2023).

[3] Sau et

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O401-02 -B3-O401-03

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Evolutionary
SearchforSuperconducting
PhasesintheLanthanum-Nitrogen-Hydrogen System with Universal Neural Network
Potential PFP*

Takahiro Ishikawa1, Shinji Tsuneyuki1

1

Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan*

takahiro.ishikawa@phys.s.u-tokyo.ac.jp
Keywords: Hydride, Superconductivity, Evolutionary algorithm, First-principles calculations, Universal neuralnetwork potential
Lanthanum hydride (La-H) has attracted much attention as a potential candidate for room-temperature
superconductivity since the discovery of the superconductivity at 260 K at pressure of 170 GPa1,2. Further
experiments for the La-H system revealed that the superconducting critical temperature Tc shows further increase
to 556 K by subsequent thermal excursions to high temperatures3. Although the reason for the significant
enhancement of Tc remains unknown, it has been considered that the enhancement is caused by some reactionsof the La-H compounds with nitrogen (N) and boron (B) originating from ammonia borane, NH3BH3, used for ahydrogen-source material. Hence, it is crucial to search for stable phases in the La-N-H, La-B-H, and La-B-N-H
systems and verify whether they show high-Tc superconductivity.
In this study, we searched for stable and metastable phases in the La-N-H system at 20 GPa using theevolutionary construction scheme of a formation-energy convex hull4. At each generation, first, we quickly
optimized a few thousand structures created by our search scheme using universal neural network potentials
named Preferred Potential (PFP)5 version 3.0.0 on Matlantis6, and then extracted only a few ten structures
emerging in the region ofΔH ≦ 4.4 mRy/atom, where ΔH denotes the enthalpy difference to the convex.
Next, for the extracted structures, we performed structural optimization based on the density functional theory
with the Quantum ESPRESSO (QE) code7 and updated the convex hull. We repeated this process up to the 8th
generation. For the stable compounds, we calculated the electron-phonon coupling constant λ and the logarithmic
averaged phonon frequency ωlog using the QE code7 and evaluated Tc using the Allen-Dynes formula8.
We obtained La3NH6, LaNH2, La2NH3, La2N5H9, LaN2H3, and La5N2H3 as stable ternary compounds, and
La3NH4, La6N2H9, and La5NH4 as moderately metastable ones which can be synthesized by experiments. In
these hydrides, La3NH4, La6N2H9, and La5NH4 show the superconductivity at 20 GPa. The highest Tc value,
however, is 8.6 K (λ = 0.7246 and ωlog = 217 K) predicted in La3NH4, which is far from high Tc
superconductivity.
This work is supported by ENEOS Corporation.

References:1) M. Somayazulu, M. Ahart, A. K. Mishra, Z. M. Geballe, M. Baldini, Y. Meng, V. V. Struzhkin, R. J. Hemley,
Phys. Rev. Lett. 122, 027001 (2019).
2) A. P. Drozdov, P. P. Kong, V. S. Minkov, S. P. Besedin, M. A. Kuzovnikov, S. Mozaffari, L. Balicas, F. F.
Balakirev, D. E. Graf, V. B. Prakapenka, E. Greenberg, D. A. Knyazev, M. Tkacz, and M. I. Eremets. Nature
569, 528 (2019).
3) A. D. Grockowiak, M. Ahart, T. Helm, W. A. Coniglio, R. Kumar, K. Glazyrin, G. Garbarino, Y. Meng, M.
Oliff, V. Williams, N. W. Ashcroft, R. J. Hemley, M. Somayazulu, and S. W. Tozer, Front. Electron. Mater. 2,
837651 (2022).
4) T. Ishikawa and T. Miyake, Phys. Rev. B 101, 214106 (2020).
5) S. Takamoto, C. Shinagawa, D. Motoki, K. Nakago, W. Li, I. Kurata, T. Watanabe, Y. Yayama, H. Iriguchi,
Y. Asano, T. Onodera, T. Ishii, T. Kudo, H. Ono, R. Sawada, R. Ishitani, M. Ong, T. Yamaguchi, T. Kataoka, A.
Hayashi, N. Charoenphakdee, and T. Ibuka, Nat Commun 13, 2991 (2022).
6) Matlantis (https://matlantis.com/), software as a service style material discovery tool.
7) P. Giannozzi et al., J. Phys.: Condens. Matter 21, 395502 (2009).
8) P. B. Allen and R. C. Dynes, Phys. Rev. B 12, 905 (1975).

MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O401-03 -B3-O401-04 (Symposium Invited)

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Development of High-pressure Diffusion Control Method for Synthesizing
Metastable Materials*M. Fujioka1, 2
1

Innovative Functional Materials Research Institute, National Institute of Advanced Industrial Science andTechnology (AIST), 2 Research Institute for Electronic Science, Hokkaido University*
m.fujioka@aist.go.jp
Keywords: High pressure, Ion diffusion, Metastable materials
Our research interest is the synthesis of metastable materials by controlling anisotropic ion diffusion. The
controllable ions in a compound should have the weakest chemical bounding state among the constituent
elements. Additionally, other elements should be strongly connected to each other and maintain the basic crystal
structure against the diffusion of controllable ions. If such controllable ions can be extracted, introduced, or
exchanged by utilizing ion diffusion, metastable materials can be synthesized. Also, it is necessary to apply adriving force at an appropriate temperature at which only controllable ions are thermally excited. The mostcommonly used driving force is an electric field. However, this way is not applicable to electron-conducting
materials due to electrostatic shielding. On the other hand, the gradient of chemical potential (Δμ) can beavailable as the driving force regardless of electric properties.
According to this idea, some metastable materials based on ion diffusion control have been synthesized bydeveloping the synthesis methods skilfully inducing Δμ. For example, the anisotropic diffusion control (ADC)
method homogeneously extracted Na ions from a large single crystalline Na24Si136 with metallic conductivity.
Then, the cage-like covalent framework of Si136 was obtained as a metastable phase 1). The proton-driven ion
introduction (PDII) is the synthesis method that can introduce the various guest ions into host materials by
utilizing proton irradiation to solid electrolytes. The PDII successfully synthesized metastable Ag 2.5ZrTe3 byintroducing Ag ions into transition metal trichlcogenides: ZrTe3 with metallic conductivity 2).
Thus, the methods utilizing ion diffusion: ADC, and PDII, are effective in synthesizing metastablecompounds. However, such a macroscopic compositional change may cause strain due to a change in the sample
volume, forming cracks and irregularities suppressing ion diffusion. This problem is particularly conspicuous at
the grain boundaries of polycrystalline samples. In addition, during macroscopic compositional changes underhigh temperatures, materials absorb atmospheric gases, such as oxygen, and undergo unexpected chemical
reactions that compensate for the compositional changes. Thus, these factors often impede ideal material
synthesis based on anisotropic ion diffusion.
To address these challenges, we developed thehigh-pressure diffusion control (HPDC) method; the cubic
multi-anvil apparatus and the technique of ADC werecombined. Figures 1(a) and 1(b) show the conventional andnovel cells for high-pressure (HP) synthesis and HPDC,
respectively. In the novel cell, the temperature can becontrolled by energizing a heater through Cu or Mo
electrodes on the side surface so that the upper and lower
Mo electrodes are connected to the inside of the sample
space, enabling electrical processing. As shown in Figure1(c), since the temperature rises to 1000°C with an input
power of 600 W, the heater electrodes function well even in
the introduction from the side surface. In this way, HPDC
can adjust the three synthesis parameters: temperature,pressure, and voltage (Figure 1(d))3), and is also expected to
produce hydrides. The details of HPDC and the obtained
compounds will be presented at the conference.
References
1) S. Iwasaki et.al., Adv. Mater. 34, 2106754 (2022).
2) M. Fujioka et. al., Adv. Funct. Mater. 33, 2208702 (2023).
3) M. Fujioka et. al., Chem. Mater. 35, 3008-3014 (2023).

Figure 1. (a), (b) Cross section of (a) HP and(b) HPDC cell. (c) Relationship between
power and temperature. (d) Journal cover.

MRS-Japan© The Materials Research Society of Japan (MRS-J) - B3-O401-04 (Symposium Invited) -B3-O401-05

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

Synthesis of Complex Transition Metal Hydrides Containing Polynuclear
Hydride Complexes with High Hydrogen Coordination*

S. Takagi1, T. Hashimoto1, K. Otsuki1, R. Utsumi2,3, Y. Nakahira2, H. Saitoh2,3, S. Orimo1,41

Institute for Materials Research, Tohoku University, Japan, 2 National Institutes for Quantum Science andTechnology, Japan, 3 University of Hyogo, Japan, 3 Advanced Institute for Materials Research, Tohoku University,Japan*
Shigeyuki.takagi.c5@tohoku.ac.jp
Keywords: Complex Transition Metal Hydrides, High Hydrogen Coordination, Polynuclear Hydride Complexes
Hydrogen exhibits an exceptionally rich chemistry, forming various chemical bonds in hydrides. The
chemical flexibility is a source of many interesting functionalities of hydrides.1) Especially, the discovery of thesuperconductivity at 203 K in the sulfur hydride system2) has spurred tremendous research activities toward the
exploration of hydrogen-rich materials.
The complex transition metal hydrides are a class of typical hydrogen-rich materials. In these hydrides, anumber of H atoms covalently bind to a single transition metal to form various homoleptic transition-metal
hydride complexes with a remarkably rich variety of hydrogen coordination modes. At the same time, transition
metals that form such complexes had been limited to the Groups 7–12;3,4) this had precluded further discovery of
hydride complexes with higher hydrogen coordination, since the coordination number tends to increase whengoing from right to left along a period due primarily to the increasing trend in the atomic size, which allows
more H atoms to bind. In this regard, we have overcome the limitation using high-pressure and high-temperature(HPHT) technique and successfully synthesized a novel complex transition metal hydride Mg3CrH8 containing
the first Group 6 hydride complex CrH75–.5) We also synthesized novel complex transition-metal hydrides
Li6NbH11, Li6TaH11, Li5MoH11, and Li5WH11 containing Groups 5 and 6 hydride complexes with ninefold
hydrogen coordination, NbH94− , TaH94− , MoH93− , and WH93− , respectively6).
H
In this study, we searched for novel complex transition metalHfhydrides containing the first Hf-based hydride complex with highhydrogen coordination by means of theoretical prediction and in-situ
synchrotron X-ray diffraction measurements. We found that Hf forms abinuclear hydride complex, where two gyroelongated square pyramidal
HfH9 units share four H atoms to form Hf2H146- (Fig. 1). The detailed Fig. 1. Structure6- of novel binuclear hydridecomplex Hf2H14 .
results will be discussed in the presentation.
This work was supported by JSPS KAKENHI (Grant No. JP23H01679), the Murata Science Foundation,
MEXT/JSPS KAKENHI (Grant Nos. JP18H05513 and JP18H05518, “Hydrogenomics”), and the QST
Advanced Research Infrastructure for Materials and Nanotechnology under the remit of “Advanced Research
Infrastructure for Materials and Nanotechnology” of the Ministry of Education, Culture, Sports, Science andTechnology (MEXT), Japan (Proposal No. JPMXP1223QS0016). The synchrotron radiation experiments were
performed using a QST experimental station at QST beamline BL14B1, SPring-8, with the approval of the Japan
Synchrotron Radiation Research Institute (JASRI) (SPring-8 Proposal No. 2023A3680).
References
1) S. Takagi and S. Orimo, Scripta Mater. (Viewpoint paper) 109, 1 (2015).
2) A. P. Drozdov, M. I. Eremets, I. A. Troyan, V. Ksenofontov and S. I. Shylin, Nature 525, 73 (2015).
3) W. Bronger, Angew. Chem. 30, 759 (1991).
4) K. Yvon, CHIMIA 52, 613 (1998).
5) S. Takagi, Y. Iijima, T. Sato, H. Saitoh, K. Ikeda, T. Otomo, K. Miwa, T. Ikeshoji, K. Aoki and S. Orimo,
Angew. Chem. Int. Ed. 54, 5650 (2015).
6) S. Takagi, Y. Iijima, T. Sato, H. Saitoh, K. Ikeda, T. Otomo, K. Miwa, T. Ikeshoji and S. Orimo, Sci. Rep. 7,44253 (2017).

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MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, JapanAbstract Guideline (Leave two lines for presentation number)

Mn-rich Al–Mn alloy hydrides synthesized under high pressure and hightemperature with the aid of in-situ synchrotron radiation X-ray diffraction
measurement
R. Utsumi1,2, S. Ajito3, Y. Nakahira1, *H. Saitoh1,2, T. Watanuki1,2, T. Sato4, S. Takagi3,
E. Akiyama3 and S. Orimo3
1

National Institutes for Quantum Science and Technology, 2 University of Hyogo, 3 Tohoku University,
Shibaura Institute of Technology*
saito.hiroyuki@qst.go.jp
Keywords: Hydride, High-pressure synthesis, Synchrotron radiation X-ray diffraction, Al-Mn alloy
4

In general, hydrides have been synthesized by mixing elements with low and high hydrogen affinities. We have
tried to synthesize novel metal hydrides containing only metals with low hydrogen affinity by using a high-pressureand high-temperature method. We have succeeded in synthesizing some Al–transition metal (TM) hydrides (e.g.
Al3FeH4 [1], Al2CuH3 [2]), where Al, Fe and Cu have low hydrogen affinities. It is noteworthy that hydrogenationof Al–TM alloys were considered difficult due to the very low hydrogen affinity of aluminum. To broaden thevariety of Al-containing hydrides and realize light-weight inexpensive Al-based hydrogen storage materials, wehave searched novel Al-TM hydrides under high pressure. In the present study, we have tried to synthesize Mnrich Al-Mn alloy hydrides that had not yet been investigated.
AlxMn1-x (x = 0.1, 0.2, 0.3) alloys with a β-Mn-type
structure produced in solid state reactions at high pressures
were used as starting materials. The samples werehydrogenated at a hydrogen pressure of 9 GPa and 750℃
for 2 h using a cubic-type multi-anvil press. We investigatedthe crystal structures of the samples during hydrogenation
reactions by in-situ synchrotron radiation X-ray diffraction
measurement system at BL14B1, SPring-8. Hydrogen
evolution from the recovered samples was investigatedusing a thermal desorption spectroscopy system forhydrogen analysis (HTDS).
Novel AlxMn1-x (x = 0.1, 0.2, 0.3) alloy hydrides with ahexagonal close-packed (hcp) structure were synthesized at
9 GPa and 750℃. Figure 1 shows in-situ powder X-ray
diffraction profiles of the Al0.3Mn0.7 alloy in fluid hydrogen.
The crystal structure of the sample changed from a β-Mntype structure to an hcp structure a few minutes after the
sample was heated to 750℃ at 9 GPa in fluid hydrogen,indicating a formation of a novel Al0.3Mn0.7 alloy hydridewith an hcp structure. The sample was cooled to room
temperature and then depressurized to ambient pressure.
The hcp phase was recovered at ambient conditions.
Fig. 1. In situ synchrotron radiation X-ray powder diffraction
The atomic ratio between hydrogen and metal atoms profiles of Al0.3Mn0.7 alloy in fluid hydrogen. Triangles andrepresent Bragg peaks from β-Mn-type and hcp(H/M) of the recovered Al–Mn alloy hydrides decreased circles
structures, respectively.
with increasing Al content. H/M of the recovered AlxMn1-x(x = 0.1, 0.2, 0.3) alloy hydrides were estimated to be 0.85,
0.56 and 0.45, respectively. Furthermore, the hydrogen release temperature of the recovered AlxMn1-x (x = 0.2, 0.3)
alloy hydrides increased with increasing Al content.
This work was supported by Grant-in-Aid for JSPS Fellows No.23KJ1856, JSPS KAKENHI (Nos. JP18H05513
and JP22H01821), and grants from the Inter-University Cooperative Research Program of the Institute forMaterials Research, Tohoku University (202012-RDKGE-0066, 202012-RDKGE-0066, and 202212-RDKGE0068) .
References:
1) H. Saitoh, T. Sato, M. Tanikami, K. Ikeda, A. Machida, T. Watanuki et al., Mater. Des. 208, 109953 (2021).
2) H. Saitoh, S. Takagi, N. Endo, A. Machida, K. Aoki, S. Orimo et al., APL Mater. 1, 032113 (2013).
MRS-Japan© The Materials Research Society of Japan (MRS-J)- B3-O401-06 -B3-O401-07

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting
December 11-16, 2023, Kyoto, Japan

High-pressure and high-temperature synthesis of novel hydrides with theaid of in-situ synchrotron radiation x-ray diffraction measurement*

Hiroyuki Saitoh1

National Institutes for Quantum Science and Technology
saito.hiroyuki@qst.go.jp
Keywords: Metal hydrides, High pressure and high temperature, Synchrotron radiation x-ray diffraction,
Aluminum-based alloys
1*

Exploration of novel hydrides is underway due to their wide range of functionalities such as hydrogen storage,
high-temperature superconductivity, fast ionic conduction, and H− conduction. Hydrogenation reactions ofmetals are one of the simple methods to obtain hydrides. Since hydrogenation reactions are thermodynamically
expected to proceed more easily at high pressure and high temperature, high-pressure and high-temperaturesynthesis is one of the effective methods for the exploration of novel hydrides.
The advantages of high-pressure hydrogenation generally become more pronounced above 1 GPa. There aremainly two kinds of apparatuses for hydrogenating metals under such high pressure. One is a diamond anvil cell,which pressurizes the sample with diamonds, and the other is a multi-anvil press, which can apply high pressure
to a relatively large volume of sample using hydraulic presses. The author’s group have synthesized novel
hydrides under high pressure up to 10 GPa using a cubic-type multi-anvil press.
In high-pressure and high-temperature synthesis, pressure is added to the synthesis parameters, which
complicates the determination of synthesis conditions. In addition, since it is difficult to obtain information on asample under high pressure, synthesis conditions are gradually changed and the recovered samples are analyzed
under ambient pressure to optimize the synthesis conditions.
We have used in-situ synchrotron radiation x-ray diffraction technique to detect the progress of novelhydrogenation reaction, which enables us to optimize the synthesis conditions effectively1). Figure shows the
optical photograph of the high-pressure apparatus. We have synthesized novel hydrides, especiallyaluminum-based alloy hydrides, by using the apparatus. Recent results of syntheses of aluminum-based hydrides
will be presented2,3).
This work was supported by JSPS KAKENHI (Nos. JP18H05513 and JP22H01821), and grants from theInter-University Cooperative Research Program of the Institute for Materials Research, Tohoku University(202012-RDKGE-0066, 202012-RDKGE-0066, and 202212-RDKGE-0068) .

Figure. Optical photograph of the cubic-type multi-anvil apparatus installed on thebeamline BL14B1, SPring-8.
References:
1) H. Saitoh, A. Machida and K. Aoki, Chin. Sci. Bull. 59, 5290 (2014).
2) H. Saitoh, T. Sato, M. Tanikami, K. Ikeda, A. Machida, T. Watanuki et al., Mater. Des. 208, 109953 (2021).
3) H. Saitoh, S. Takagi, N. Endo, A. Machida, K. Aoki, S. Orimo et al., APL Mater. 1, 032113 (2013).

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Late Breaking News | B. Energy | Late Breaking News

[B-L304] Late Breaking News
Wed. Dec 13, 2023 6:30 PM - 8:30 PM Poster (Annex)[B-L304-01] Epitaxial Growth of LaHx Thin Films and Hydrogen Diffusion at the LaHx
/Zr Interface*Ziyang Cao1, Daichi Miyazaki1, Takuto Soma1, Akira Ohtomo1 （1. Tokyo Tech. (Japan)）[B-L304-02] Laser-Induced Graphene: A Three-Dimensional Electrocatalyst Support
for Efficient Oxygen and Hydrogen Evolution in Alkaline Media*IBRAHIM KHAN1, Sanghyuk Wooh1 （1. Chung Ang University (Korea)）[B-L304-03] Temporally Modulated Thermoelectricity*Jose Ordonez1, Roman Anufriev1, Masahiro Nomura1, Sebastian Volz1 （1. CNRS - The
University of Tokyo (Japan)）[B-L304-04] Tuning the Spin-Valence States of Atomically Dispersed Vanadium on
Carbon-based Substrates for Oxygen Reduction Reactions*Jessie Manopo1, Yudi Darma1 （1. Institut Teknologi Bandung (Indonesia)）[B-L304-05] Design of N-Type Textured Bi2Te3 with Robust Mechanical Properties
for Thermoelectric Micro-Refrigeration Application*Yu-Ke Zhu1, Zihang Liu1, Jiehe Sui1 （1. State Key Laboratory of Advanced Welding andJoining, Harbin Institute of Technology, Harbin 150001, China. (China)）[B-L304-06] Thermal Stability Improvement of Nanostructured MgAgSb Bulk
Materials Through Grain Boundary Segregation*Lei Jiao1, Yuan Yu2, Jiehe Sui1, Zihang Liu1 （1. State Key Laboratory of Advanced Welding
and Joining, Harbin Institute of Technology, Harbin 150001. (China), 2. I. Physikalisches
Institut (IA), RWTH Aachen University, 52056 Aachen. (Germany)）[B-L304-07] Ternary Pt– Ni– Au alloy catalyst for Oxygen Reduction Reaction*xianxian xie xie1 （1. Charles University (Czech Republic)）[B-L304-08] Navigating a Visible-driven Photocatalyst for Efficient Green Hydrogen
Generation*Shin Chwen Yeh1, Wen Yin Ko1, Kuan Jiuh Lin1 （1. National Chung Hsing University(Taiwan)）[B-L304-09] Fast proton conducting acid-base nanocomposite membranes withfunctional silanes*Yeji park1, SuMin Jeong1, Md Shahjahan Kabir Chowdury1, SungBum Park2, Yong-il Park1（1. Kumoh National Institute of Tech. (Korea), 2. Dongguk Univ. WISE Campus (Korea)）[B-L304-10] Improvement of Proton Transfer Channels through Acid-Base Pairs inProton Exchange Membrane Fuel Cells (PEMFCs)*Md Shahjahan Kabir Chowdury1, Ye Ji Park1, Jeong Su Min Jeong1, Sung Bum Park2, Yong-il
Park1 （1. Kumoh National Institute of Technology (Korea), 2. Dongguk University Gyeongju(Korea)）[B-L304-11] Record-high thermoelectric performance in Al-doped ZnO via
Anderson localization of band edge states*Illia Serhiienko1,2, Takao Mori1,2 （1. University of Tsukuba (Japan), 2. National Institute forMaterials Science (Japan)）©The Materials Research Society of JapanMRM2023/IUMRS-ICA2023[B-L304-12] Polaron Surface State Nanomaterials for Green Energy Conversion
Devices*Yi-Sheng Lai1, Hung-Yu Shen1, Min-Chi Chen1 （1. National of Chung Cheng University(Taiwan)）[B-L304-13] Role of H permeation on surface oxidation of Ni-based alloy in hightemperature water environment*ZIHAO WANG1, Tetsuo Shoji3, Yutaka Watanabe3, Yoichi Takeda3, Zhengcao Li2, Sergio
Lozano-Perez1 （1. Univ. of Oxford (UK), 2. Tsinghua Univ. (China), 3. Tohoku Univ. (Japan)）[B-L304-14] Magnesium-Based Metallic Glass for Brazing Paste Application in
Thermoelectric Module Fabrication*Soon-Mok Choi1, Hyukjun Youn1, Soonil Lee2, Kyu-Mann Lee1 （1. School of Energy,
Materials and Chemical Engineering, Korea University of Technology and Education (Korea),
2. School of Materials Science and Engineering / Department of Materials Convergence andSystem Engineering (Korea)）©The Materials Research Society of Japan

B3-O201-03

MRM2023/IUMRS-ICA2023

MRM2023/IUMRS-ICA2023 Grand Meeting

December 11-16, 2023, Kyoto, Japan

Epitaxial Growth of LaHx Thin Films and Hydrogen Diffusion at the
LaHx/Zr Interface*

Z. Cao1, D. Miyazaki1, T. Soma1, A. Ohtomo1

Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan.
cao.z.aa@m.titech.ac.jp
Keywords: Metal hydrides, Pulsed-laser deposition, Interface, Hydrogen diffusion1*Lanthnum hydrogen compounds have recently gained attention due to the discovery of high-temperature
superconductivity in LaH10+x and fast hydride-ion conduction in LaH3‒2xOx. On the other hand, it is known that
LaHx (2 ≤ x ≤ 3) transitions from a metal to an insulator with increasing x [1]. To apply these materials fordeveloping solid-state ionic devices, it is important to investigate dynamics of hydrogen diffusion in an ideal
sample. We previously synthesized oriented thin films of group IV hydrides using pulsed-laser deposition (PLD)
technique, and revealed their unique properties [2]. Building upon this progress, in the present study, we focusedon the fabrication of LaHx epitaxial films. This allows us to investigate the diffusion of hydrogen at metalizedinterface between LaHx and Zr.
In our experimental setup, pressed LaHx pellet was used as a target for PLD, and (111)-oriented LaHx thin films
with a thickness of ~70 nm were grown on Al2O3 (0001) substrates at room temperature under vacuum condition.
The crystal structure of the films was investigated by x-ray diffraction (XRD). No trace of LaOx phases suggeststhat a capping layer of 200-nm-thick amorphous Al2O3 (a-Al2O3) prevented LaHx from oxidation. Furthermore,when the bilayer films were annealed under vacuum conditions at 230 °C, the formation of Zr hydride phases wasobserved after 104-sec-annealing, suggesting the diffusion of hydrogen from the LaHx to Zr layers [Fig. 1 (a)]. The
characteristic lattice spacing are plotted in Fig. 1 (b). The original hcp lattice of as-grown Zr layer tends to expand
and disappear due to hydrogen incorporation, while a new phase assignable to δ-ZrH2 or ZrHx (x > 2) appears. Thisphenomenon adds an intriguing aspect to create multilayered structures with metalized interfaces between, forexample, LaH3‒2xOx and ZrHx in terms of applications to solid-state ionic devices.

Fig. 1. (a) XRD profiles for the LaHx thin films on Zr layer, forming a bilayer structure on the Al2O3 substrate. Insets depict schematic sample
cross-sections of the as grown film. Note that all the samples are covered with a-Al2O3 layers. (b) Lattice spacing d111 as a function of
annealing time. Filled and open circles indicate Zr phase and H-rich ZrHy phase, respectively. Broken lines show literature values of bulks.
Error bars indicate full width at half maximum for each peak.

References:1) K. Fukui, S. Iimura, A. Iskandarov, T. Tada, H. Hosono, J. Am. Chem. Soc. 144, 1523-1527 (2022).
2) K. Yoshimatsu, T. Suzuki, N. Tsuchimine, K. Horiba, H. Kumigashira, T. Oshima, A. Ohtomo, Appl. Phys.
Express 8, 6–10 (2015).
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