[6a-S44-1~10] 9.2 Nanowires and Nanoparticles

▲ [6a-S44-3] On-board Hydrogen Storage in Pd_xPt_1-x Solid-solution Nanoparticles

〇(PC)Rosantha Kumara¹, Osami Sakata¹, Hirokazu Kobayashi², Chulho Song¹, Toshiki Yoshimoto³, Satoru Yoshioka³, Syo Matsumura³, Hiroshi Kitagawa² (1.NIMS/SPring-8, 2.Kyoto Univ., 3.Kyushu Univ.)

Keywords:Nanoparticles, Hydrogen Storage, Electronic structure

Hydrogen is an energy carrier like electricity and it can be produced from hydrocarbons and electrolysis of water. It is the fuel having the highest energy density. One of the most critical problem in hydrogen technology is transportation and on-vehicle storage of hydrogen. However, solid-state nanomaterials for hydrogen storage offer best opportunity for developing the technology required for on-board applications. Palladium is famous for hydrogen storage in both its bulk and nanoparticle (NP) forms. The hydrogen-storage capacity of the Pd_xPt_1-x solid-solution NPs can be tuned by changing the composition of Pd and Pt. Specially, Pd_xPt_1-x solid-solution NPs with 0.79 ≤ x ≤ 0.92 possessed a higher hydrogen-storage capacity than Pd NPs and Pd/Pt core/shell NPs. Recent studies have suggested that the hydrogen dissociation of the Pd_xPt_1-x solid-solution alloy is proportional to the hydrogen-metal bond strength and to the d-band states near the Fermi level. In this study, the correlation between the electronic structure properties such as the unoccupied electronic states and their density of states, and the hydrogen storage and stability properties of the Pd_xPt_1-x solid-solution NPs were investigated by mean of synchrotron X-ray absorption near-edge structure (XANES) and hard X-ray photoelectron spectroscopy (HAXPES).