Development of hydrogen oxidation reaction catalysts to overcome CO poisoning and elucidation of reaction mechanism

Inagawa, Kohei*; Matsumura, Daiju; Taniguchi, Masashi*; Uegaki, Shinya*; Nakayama, Tomohito*; Urano, Junnosuke*; Aotani, Takuro*; Tanaka, Hirohisa*

Journal of Physical Chemistry C, 127(24), p.11542 - 11549, 2023/06

https://doi.org/10.1021/acs.jpcc.3c02237

Electron storage performance of hybrid materials comprising polyoxometalates and carbon nanohorns as cathode-active materials

Wakamatsu, Katsuhiro*; Sekihara, Akihori*; Yamaguchi, Yoshihiko*; Matsushima, Ryo*; Matsumura, Daiju; Kuila, T.*; Yoshikawa, Hirofumi*

Batteries & Supercaps (Internet), 6(1), p.e202200385_1 - e202200385_8, 2023/01

https://doi.org/10.1002/batt.202200385

Performance tests of catalysts for the safe conversion of hydrogen inside the nuclear waste containers in Fukushima Daiichi

Reinecke, E.-A.*; Takenaka, Keisuke*; Ono, Hitomi*; Kita, Tomoaki*; Taniguchi, Masashi*; Nishihata, Yasuo; Hino, Ryutaro; Tanaka, Hirohisa*

International Journal of Hydrogen Energy, 46(23), p.12511 - 12521, 2021/03

https://doi.org/10.1016/j.ijhydene.2020.08.262

The safe decommissioning as well as decontamination of the radioactive waste resulting from the nuclear accident in Fukushima Daiichi represents a huge task for the next decade. At present, research and development on long-term safe storage containers has become an urgent task with international cooperation in Japan. One challenge is the generation of hydrogen and oxygen in significant amounts by means of radiolysis inside the containers, as the nuclear waste contains a large portion of sea water. The generation of radiolysis gases may lead to a significant pressure build-up inside the containers and to the formation of flammable gases with the risk of ignition and the loss of integrity. In the framework of the project "R&D on technology for reducing concentration of flammable gases generated in long-term waste storage containers" funded by the Japanese Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), the potential application of catalytic recombiner devices inside the storage containers is investigated. In this context, a suitable catalyst based on the so-called intelligent automotive catalyst for use in a recombiner is under consideration. The catalyst is originally developed and mass-produced for automotive exhaust gas purification, and is characterized by having a self-healing function of precious metals (Pd, Pt and Rh) dissolved as a solid solution in the perovskite type oxides. The basic features of this catalyst have been tested in an experimental program. The test series in the REKO-4 facility has revealed the basic characteristics of the catalyst required for designing the recombiner system.

General synthesis of single-atom catalysts for hydrogen evolution reactions and room-temperature Na-S batteries

Lai, W.-H.*; Wang, H.*; Zheng, L.*; Jiang, Q.*; Yan, Z.-C.*; Wang, L.*; Yoshikawa, Hirofumi*; Matsumura, Daiju; Sun, Q.*; Wang, Y.-X.*; et al.

Angewandte Chemie; International Edition, 59(49), p.22171 - 22178, 2020/12

https://doi.org/10.1002/anie.202009400

Pyroelectric power generation from the waste heat of automotive exhaust gas

Kim, J.*; Yamanaka, Satoru*; Murayama, Ichiro*; Kato, Takanori*; Sakamoto, Tomokazu*; Kawasaki, Takuro; Fukuda, Tatsuo; Sekino, Toru*; Nakayama, Tadachika*; Takeda, Masatoshi*; et al.

Sustainable Energy & Fuels (Internet), 4(3), p.1143 - 1149, 2020/03

https://doi.org/10.1039/C9SE00283A

Electrochemical adsorption on Pt nanoparticles in alkaline solution observed using in situ high energy resolution X-ray absorption spectroscopy

Kusano, Shogo*; Matsumura, Daiju; Ishii, Kenji*; Tanaka, Hirohisa*; Mizuki, Junichiro*

Nanomaterials (Internet), 9(4), p.642_1 - 642_14, 2019/04

https://doi.org/10.3390/nano9040642

Temperature stability of PIN-PMN-PT ternary ceramics during pyroelectric power generation

Moro, Takuya*; Kim, J.*; Yamanaka, Satoru*; Murayama, Ichiro*; Kato, Takanori*; Nakayama, Tadachika*; Takeda, Masatoshi*; Yamada, Noboru*; Nishihata, Yasuo; Fukuda, Tatsuo; et al.

Journal of Alloys and Compounds, 768, p.22 - 27, 2018/11

https://doi.org/10.1016/j.jallcom.2018.07.182

Effects of randomness and frustration on the relaxor nature in Pb(InNb)O

Owada, Kenji

Nihon Kessho Gakkai-Shi, 54(3), p.147 - 154, 2012/06

https://doi.org/10.5940/jcrsj.54.147

It is well known that B-site randomness contributes to the appearance of relaxor phenomena in the lead-based complex perovskite Pb(B'B'')O. But the microscopic mechanism of the effect of B-site randomness on the systems has not been understood yet. Among the Pb(B'B'')O systems, Pb(InNb)O (PIN) has drawn much attention because it can be in the antiferroelectric (AFE), ferroelectric (FE), or relaxor state depending on B-site randomness. We review the recent progress in our understanding of the effect of B-site randomness on PIN from the experimental viewpoint. As a conclusion of the arguments, we also introduce the frustration mechanism in Pb(B'B'')O.

Antiferroelectric correlation in relaxor Pb(InNb)O and ferroelectric correlation in antiferroelectric Pb(InNb)O

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Baron, A. Q. R.*; Mizuki, Junichiro; Owa, Hidehiro*; Yasuda, Naohiko*

Transactions of the Materials Research Society of Japan, 34(1), p.19 - 22, 2009/03

https://doi.org/10.14723/tmrsj.34.19

Pb(InNb)O (PIN) can be antiferroelectric (AFE), ferroelectric (FE) or a relaxor depending upon the perovskite B-site randomness. This is characterized by measurements of dielectric response, which shows behavior that is usually clearly in one of those three classes. In contrast, X-ray scattering studies suggest the presence of AFE correlation in the relaxor state and FE in AFE state. Weak phonon softening at zone boundary in relaxor state shows that the AFE correlation intrinsically exists in PIN, as does the corresponding elastic scattering at (/2 /2 0), while weak diffuse scattering around 333 Bragg reflection appears in AFE state suggesting FE correlation. These results will support our previous speculation that the AFE and FE correlations coexist in PIN (K. Owada ., Phys, Rev. B 094136 (2008)). Such a coexistence or competition is widely seen in the perovskite relaxor and the coexistence of FE and AFE correlations is essential for generating relaxor state.

Spatial distribution of the B-site inhomogeneity in an Pb(InNb)O single crystal studied by a complementary use of X-ray and neutron scatterings

Owada, Kenji; Hirota, Kazuma*; Terauchi, Hikaru*; Owa, Hidehiro*; Yasuda, Naohiko*

Journal of the Physical Society of Japan, 75(2), p.024606_1 - 024606_6, 2006/12

https://doi.org/10.1143/JPSJ.75.024606

Structural properties of Pb(InNb)O (PIN) single crystals at room temperature (RT) were investigated by X-ray and neutron scattering techniques, taking much account of the difference in the penetration depth and spatial resolution of X-rays and those of neutrons. A strong diffuse scattering was observed by X-ray while h/4, k/4, 0 superlattice reflections were found by neutron, indicating a relaxor state in the outer-layer of the crystal and an antiferroelectric (AFE) state in the bulk. The phonon dispersion was measured for the first time for the PIN series. Two transverse optic (TO1 and TO2) modes were clarified near the zone center though neither water-fall behavior nor folding of phonon branches was confirmed. We have thus concluded that a major part of the PIN crystal at RT is ferroelectric (FE). These results imply that the -site chemical ordering, i.e. inhomogeneity, which controls the structural properties of PIN, is unevenly distributed throughout the crystal. We speculate that small AFE grains coexist with the FE matrix while the outer-layer is in a relaxor state in the PIN.