[2P01-53] Poster Presentation

[2P02] In situ reduction of ReO_x-Au/CeO₂ catalyst by hydrogen under near ambient pressure conditions

*Minami Obuchi¹, Ryo Toyoshima¹, Yu Murano¹, Keiichi Tomishige², Hiroshi Kondoh¹ (1. Department of Chemistry, Keio University, 2. Department of Applied Chemistry, Tohoku University)

The utilization of biomass-derived polyols includes the conversion to alkene molecules through a means known as deoxy-dehydration (DODH) reaction. In this reaction, ReO_x-Au/CeO₂ catalyst demonstrates activity. It is believed that hydrogen spillover is involved in the catalytic reaction. In this study, the chemical state of Re while flowing hydrogen gas were measured using NAP-XPS. Then we calculate the diffusion coefficient of hydrogen gas and model hydrogen diffusion. We tracked the time-dependent change in the ReO_x-Au/CeO₂ model catalyst under a hydrogen gas atmosphere (100 ℃,140 ℃ and 250 ℃,0.1 Torr) using NAP-XPS. Over time in a hydrogen atmosphere, the oxidation state of Re was reduced from 7+ to 6+ and 4+, while 2+ and 0 were not observed. The higher reduction rate observed at 250 ºC suggest that direct reduction of ReO_x by molecular hydrogen might contribute dominantly at such a high temperature. While at low temperatures below 150 ºC, where the hydrogen spillover takes place.