Presentation Information
[1P06]In situ Observation of Hydrogen Spillover on TiO2(110) Surfaces modified by Pt and FeOx: A Near Ambient Pressure XPS Study
*Hiroshi Kondoh1, Kenshin Nambu1, Yuki Tsujikawa1 (1. Keio University (Japan))
A near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) system developed at KEK-PF has been applied to in situ/operando surface characterization. In this study, we investigated the microscopic mechanisms of hydrogen spillover, a key process in catalytic hydrogenation, using NAP-XPS on a Pt-nanoparticle and FeOx-submonolayer deposited TiO2(110) single-crystal surface under near-ambient H2 conditions (0.1 Torr).
Hydrogen spillover was confirmed by the accelerated reduction of Fe3+ to Fe2+, which occurred exclusively in the presence of nanoparticles. Detailed O 1s and Ti 2p spectral analysis revealed two distinct OH species, along with Ti3+ and Ti4+ species. Notably, one of the OH species and the Ti3+ species exhibited concerted behavior with practically identical surface coverages regardless of temperature. This finding strongly suggests that these two species exist in a 1:1 ratio and migrate together. Based on these observations, a plausible mechanism for hydrogen spillover on metal oxide surfaces will be discussed.
Hydrogen spillover was confirmed by the accelerated reduction of Fe3+ to Fe2+, which occurred exclusively in the presence of nanoparticles. Detailed O 1s and Ti 2p spectral analysis revealed two distinct OH species, along with Ti3+ and Ti4+ species. Notably, one of the OH species and the Ti3+ species exhibited concerted behavior with practically identical surface coverages regardless of temperature. This finding strongly suggests that these two species exist in a 1:1 ratio and migrate together. Based on these observations, a plausible mechanism for hydrogen spillover on metal oxide surfaces will be discussed.
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