Charge Transfer Drives Hydrogen Adsorption, Spillover, and Hydroxylation at the Pt/γ-Al₂O₃ Interface

Metal–support interactions have garnered much attention due to their impact on the structure and reactivity of supported metal catalysts. Despite the widespread recognition of multifunctional mechanisms in metal/metal oxide systems, much less attention has been paid to how the metal influences its support. Here, we explore metal–support interactions using hydrogen adsorption on a dehydroxylated γ-Al2O3(110) supported Pt10 cluster as a prototype. Through molecular dynamics simulations performed using an actively trained machine-learned force field, we observed reversible hydrogen spillover between the support and the metal. Analysis of the electronic structure and chemical nature of the interface reveals that charge transfer from H to the Pt10 cluster drives the spillover by stabilizing H adsorbed on the support. The same charge transfer concept also explains the stabilization of OH fragments at the Pt10/γ-Al2O3(110) interface despite the scarcely impacted or even reduced acidity of interfacial Al sites. These findings demonstrate the rich chemistry of metal–support interfaces and the importance of “inverse” effects in the fundamental understanding of supported catalysts.金属-载体相互作用（Metal–support interactions）因其对负载型金属催化剂的结构与反应活性具有显著影响，而受到广泛关注。尽管学界已充分认识到金属/金属氧化物体系存在多作用机制，但针对金属如何反作用于载体的研究却相对匮乏。本研究以经脱羟基处理的γ-氧化铝(110)晶面负载的Pt₁₀团簇为模型体系，通过氢吸附过程探究金属-载体相互作用。本研究采用主动训练的机器学习力场（machine-learned force field）开展分子动力学模拟，观测到载体与金属之间发生了可逆氢溢流现象。通过对界面电子结构与化学本质的分析，我们发现氢原子向Pt₁₀团簇的电荷转移，通过稳定吸附在载体上的氢物种，成为驱动氢溢流的核心因素。该电荷转移机制同样可以解释Pt₁₀/γ-氧化铝(110)界面处OH片段的稳定存在：尽管界面处铝位点的酸性几乎未受影响，甚至有所降低。本研究结果揭示了金属-载体界面丰富的化学特性，并阐明了“反向”效应在负载型催化剂基础研究中的重要意义。