Unveiling the Formation Mechanisms of the Pt-Sn Intermetallic Phase within Pt-SnO₂ for the Enhanced Hydrogen Evolution Reaction.

Abstract

Unraveling the dynamic metal-support interactions of heterogeneous catalysts during the pretreatment environment is pivotal for modulating the phase structure and improving electrochemical activities. Here, we first investigate the hydrogen evolution reaction activity of Pt-SnO₂ catalysts treated under different temperatures. Subsequently, assisted by both experimental observations and density functional theory calculations, we provide atomic-scale insights into the reactive interaction between Pt nanoparticles and SnO₂ nanowires. The Pt nanoparticles gradually transform into Pt₃Sn, PtSn, and PtSn₂ intermetallic phases with increasing temperature, induced by the interlayer diffusion of Sn atoms. Finally, the catalytic activities of Pt-SnO₂ can be well-interpreted based on the nucleation of different intermetallic phases. Our results provide perspectives into the structure-property interplay in a metal/oxide heterogeneous catalyst, thus offering guidance for optimizing the catalytic performance.