Sustained Hydrogen Spillover on Pt/Cu(111) Single-Atom Alloy: Dynamic Insights into Gas-Induced Chemical Processes

Hydrogen spillover, involving the surface migration of dissociated hydrogen atoms from active metal sites to the relatively inert catalyst support, plays a crucial role in hydrogen-involved catalytic processes. However, a comprehensive understanding of how H atoms are driven to spill over from active sites onto the catalyst support is still lacking. Here, we examine the atomic-scale perspective of the H spillover process on a Pt/Cu(111) single atom alloy surface using machine-learning accelerated molecular dynamics calculations based on density functional theory. Our results show that when an impinging H₂ dissociates at an active Pt site, the Pt atom undergoes deactivation due to the dissociated hydrogen atoms that attach to it. Interestingly, collisions between H₂ and sticking H atoms facilitate H spillover onto the host Cu, leading to the reactivation of the Pt atom and the realization of a continuous H spillover process. This work underscores the importance of the interaction between gas molecules and adsorbates as a driving force in elucidating chemical processes under a gaseous atmosphere, which has so far been underappreciated in thermodynamic studies.