Browsing by Author "Matsumura, S"

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    Hydrogen sorption behaviour of Mg-5wt.%La alloys after the initial hydrogen absorption process
    (Elsevier B. V., 2022-04-29) Kim, MJ; Tan, XF; Gu, QF; McDonald, SD; Ali, Y; Matsumura, S; Nogita, K
    In our earlier study, it has been shown that trace Na additions can improve the reaction kinetics of Mg–5%La (wt.%) alloys during the first absorption. However, the subsequent hydrogen desorption/absorption process of the Mg–5%La after the first absorption has not been investigated. In this study, we have investigated the hydrogen sorption behaviour of the Mg–5%La alloy after the first absorption in terms of phase evolution, and lattice expansion properties during desorption as function of temperature using in-situ synchrotron Powder X-ray Diffraction (PXRD) and in-situ High Voltage Transmission Electron Microscopy (HVTEM). Two distinct phase evolutions, a continuous phase transformation of LaH3 → LaH2 + ½ H2 (from 250 °C) and decomposition of MgH2 → Mg + H2 (between 440 and 460 °C) were identified during the desorption. It is determined that this alloy is cyclable in the absence of Mg12La intermetallic during the subsequent absorption/desorption cycling after the first hydrogen absorption. © 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd
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    In-situ x-ray diffaction for hydrogen sorption study of Mg-La alloys
    (Australian Nuclear Science and Technology Organisation, 2021-11-24) Kim, MJ; Tan, XF; Gu, QF; McDonald, SD; Ali, Y; Matsumura, S; Nogita, K
    Trace Na additions can enhance the reaction kinetics of Mg-5%La (wt.%) alloys, resulting in a potential hydrogen storage material. In this study, we used in-situ synchrotron Powder X-ray Diffraction (PXRD) to examine the hydrogen sorption behaviour of the Na-modified Mg-5%La. A setup equipped with a hydrogen gas flow cell and a hot air blower at the Powder Diffraction beamline of the Australian Synchrotron facility is used to allow for PXRD data collection during hydrogen sorption reactions to study the phase evolutions and the cyclability of the alloy. To shed light on the underlying processes during the reactions, in-situ desorption and absorption were performed in a hydrogen atmosphere between 30-480 °C and atmospheric pressure to 2MPa H2. Rietveld refinement was conducted using the TOPAS-Academic V6 software to calculate the weight percentage and lattice expansion of each phase in the sample. In addition, in-situ High Voltage Transmission Electron Microscopy (HVTEM) was used as a complementary technique to study the volume expansion properties during desorption as a function of temperature. © The Authors