<i>Operando</i> Unveiling of Hydrogen Spillover Mechanisms on Tungsten Oxide Surfaces

Hydrogen spillover is an important process in catalytic hydrogenation reactions, facilitating H2 activation and modulating surface chemistry of reducible oxide catalysts. This study focuses on the operando unveiling of platinum-induced hydrogen spillover on monoclinic tungsten trioxide (γ-WO3), employing ambient pressure X-ray photoelectron spectroscopy, density functional theory calculations and microkinetic modeling to investigate the dynamic evolution of surface states at varied temperatures. At room temperature, hydrogen spillover results in the formation of W5+ and hydrogen intermediates (hydroxyl species and adsorbed water), facilitated by Pt metal clusters. With increasing temperature, water desorption, reverse hydrogen spillover and surface-to-bulk diffusion of hydrogen atoms compete with each other, leading initially to reoxidation and then further reduction of W atoms in the near-surface. The combined experimental results and simulations provide a comprehensive understanding of the mechanisms underlying hydrogen interaction with reducible metal oxides, lending insights of relevance to the design of enhanced hydrogenation catalysts.氢溢流（Hydrogen spillover）是催化加氢反应中的关键过程，可介导氢气活化并调控可还原氧化物催化剂的表面化学特性。本研究聚焦于铂诱导的单斜相三氧化钨（γ-WO3）上氢溢流现象的原位表征与揭示，采用环境压力X射线光电子能谱、密度泛函理论（density functional theory）计算及微观动力学建模，系统探究不同温度下催化剂表面状态的动态演化规律。室温条件下，氢溢流会在铂金属团簇的介导下生成五价钨（W5+）与氢中间体（羟基物种及吸附水）。随着温度升高，水脱附、逆氢溢流及氢原子表面到体相扩散过程相互竞争，初始阶段会引发近表面区域钨原子的再氧化，随后进一步发生还原反应。结合实验观测结果与模拟计算数据，本研究全面阐明了氢与可还原金属氧化物的相互作用机制，为高性能加氢催化剂的设计与优化提供了重要的理论参考。