| 研究実績の概要 |
The overall research is focused on the fabrication, structural elucidation and exploration of catalytic activities of amorphous and crystalline platinum-group metal (PGM) selenides.
A hot injection method was employed to prepare the selenides. The amorphous and crystalline selenides were obtained by modifying the preparation methods or thermal annealing. The amorphous and crystalline high-entropy PGM selenide with a single cubic phase was prepared for the first time. The crystallinity of monometallic selenides was also tuned. The materials were characterized by X-ray diffraction, electron microscopy, X-ray fluorescence spectroscopy, X-ray photon spectroscopy and other methods. The atomic coordination, short- and long-range order in amorphous and crystalline high-entropy selenides were systematically studied.
It was revealed that factors such as surfactant capping, precursor reactivity or nucleation/growth kinetics do not display significant roles toward amorphous structure. On the other hand, the multi-element composition contributes to the amorphous structure of high-entropy selenide probably due to various amorphous/crystalline structures of different PGM selenides. During its formation, the long-range order that could be present in the monometallic selenides is disturbed by the incorporation of other elements that favor disordered structure.
The amorphous HE-selenide exhibits superior acidic hydrogen evolution activity compared with monometallic selenides and also crystalline counterpart, demonstrating the advantages of high-entropy configuration and amorphous structure.
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