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Kim, H.*; Sakaki, Koji*; Saita, Itoko*; Enoki, Hirotoshi*; Noguchi, Kazuo*; Machida, Akihiko; Watanuki, Tetsu; Nakamura, Yumiko*
International Journal of Hydrogen Energy, 39(20), p.10546 - 10551, 2014/07
Times Cited Count:13 Percentile:32.06(Chemistry, Physical)The effect of the vanadium content on the cyclic stability of V-Ti binary alloys was investigated. VTi, 0.2 and 0.5 samples were hydrogenated and dehydrogenated at 410 K and 553 K respectively, for more than 100 times. During hydrogen cycling, reduction in the reversible hydrogen storage capacity was clearly observed from both samples. In addition, the shape of the pressure-composition-isotherm curves was significantly altered over the testing cycle period; the absorption and desorption plateaus got markedly inclined and the hysteresis became evidently smaller. We found that even after the hydrogen storage capacity of VTi was significantly reduced, at low enough temperature VTi was able to absorb hydrogen as much as it did at the first cycle.
Mitsui, Takaya; Masuda, Ryo*; Seto, Makoto; Hirao, Naohisa*; Matsuoka, Takehiro*; Nakamura, Yumiko*; Sakaki, Koji*; Enoki, Hirotoshi*
Journal of Alloys and Compounds, 580(Suppl.1), p.S264 - S267, 2013/12
Times Cited Count:8 Percentile:42.44(Chemistry, Physical)Masuda, Ryo; Mitsui, Takaya; Ito, Keiji*; Sakaki, Koji*; Enoki, Hirotoshi*; Nakamura, Yumiko*; Seto, Makoto
Hyperfine Interactions, 204(1-3), p.139 - 142, 2012/03
Times Cited Count:2 Percentile:76.72(Physics, Atomic, Molecular & Chemical)We have been developing a system for in situ Mssbauer studies using synchrotron radiation (SR) to elucidate the mechanism of hydrogenation processes. In the system, samples reacts in an atmosphere chamber and SR-based Mssbauer spectra using variable-frequency nuclear monochromator and energy spectra of inelastic nuclear resonant scattering (NRS) of SR are measured. As a feasibility study, the temperature dependence of the Mssbauer and inelastic NRS spectra of Fe in -GdFeH under vacuum were measured. In both spectra, clear differences were observed between 373 K and 573 K. These differences can be interpreted by the change of microscopic environment around Fe at the dehydrogenation. Thus, it is confirmed that this system works well enough to perform the in-situ Mssbauer study on the dehydrogenation of -GdFeH.
Masuda, Ryo; Mitsui, Takaya; Ito, Keiji*; Sakaki, Koji*; Enoki, Hirotoshi*; Nakamura, Yumiko*; Kobayashi, Yasuhiro*; Kitao, Shinji*; Seto, Makoto
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