Charge Transfer Drives Hydrogen Adsorption, Spillover, and Hydroxylation at the Pt/γ-Al<sub>2</sub>O<sub>3</sub> Interface
George Yan, Salman A. Khan, Dionisios G. Vlachos
Abstract
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-Al 2 O 3 (110) supported Pt 10 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 Pt 10 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 Pt 10 /γ-Al 2 O 3 (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.