Identification of hydrogen species on Pt/AlO by inelastic neutron scattering and their reactivity with ethylene

Yamazoe, Seiji*; Yamamoto, Akira*; Hosokawa, Saburo*; Fukuda, Ryoichi*; Hara, Kenji*; Nakamura, Mitsutaka   ; Kamazawa, Kazuya*; Tsukuda, Tatsuya*; Yoshida, Hisao*; Tanaka, Tsunehiro*

Hydrogen (H) species adsorbed on catalyst surfaces are key intermediates in catalytic hydrogenation reactions over supported metal catalysts. However, individual identification of H species on the metal catalysts has not been established to date. Here, we elucidated the H species on Pt/AlO by the combination of inelastic neutron scattering (INS) and density functional theory (DFT). Several H species in the presence of H were successfully identified at different sites on the Pt surface and AlO support. The INS and FT-IR measurements revealed that the hydride/atop Pt-H, bridged perimeter/terrace Pt-H-Pt, and threefold Pt-H are active intermediates in the CH hydrogenation reaction, whereas the edge Pt-H-Pt is a rather inert species. In addition, the measurements indicate that the AlO itself acts as hydrogen storage material by mediating AlO-H and Al-H-Al species, which serve H species in the CH hydrogenation reaction.