Hydrogen-induced oxide-to-metal charge transfer modifies catalytic sites

Journal article, 2026

Prototypical catalysts are realized as metal nanoparticles supported on a metal-oxide. It is well-known that the choice of support may have significant consequences on the catalytic activity, also in cases where the reaction is believed to occur on the metal phase. The underlying reason for this metal/oxide synergy is poorly understood, and often attributed to processes occurring at the metal/oxide interface. Here, we use density functional theory calculations to investigate the synergy between metal nanoparticles (Cu, Pd, Pt, and Au) and oxide supports (ZnO, MgO and ZrO2) in the case of hydrogen (H2) adsorption. The presence of a metal phase favors the formation of OH-groups in the oxide surface owing to a significant oxide-to-metal charge transfer, effectively charging the metal nanoparticles. The phenomenon is general and the hydrogen adsorption energy depends on the choice of oxide. For Cu, Pd, and Pt supported on ZnO, we find that the presence of a metal nanoparticle is crucial for the kinetics of H2 adsorption. H2 dissociates on the metal and occupies the oxide sites via a spillover mechanism. The hydrogen-induced charging of metal particles and formation of OH-groups advance the understanding of composite metal/oxide systems, with implications for catalytic properties.