Photo-Induced Modulation of Reactant Adsorption on AuPd Alloy for Selective Ketone Hydrogenation

The adsorption kinetics and interfacial interactions between reactants and catalyst surfaces are crucial determinants of catalytic efficiency and selectivity in heterogeneous catalysis. For ketone hydrogenation, the adsorption of both hydrogen and carbonyl groups strongly influences the reaction pathway. Although AuPd alloys are well-known for their plasmonic enhancement effects, the light-induced modulation of reactant adsorption remains unclear. Here, we employ AuPd alloys to unveil the role of visible light in regulating surface adsorption during ketone hydrogenation. Localized surface plasmon resonance (LSPR) excitation of Au was found to trigger accelerated hydrogen dissociation on the AuPd alloy surface. This process generates active AuPd–H hydride species and concurrently enhances surface charge heterogeneity. In situ XAS provides real-time observation of the subsequent, enhanced adsorption of ketone molecules via their C═O bonds. The technique offers a molecular-scale view into the enhanced C═O chemisorption on AuPd–H sites, rationalizing the highly efficient and selective hydrogenation under moderate circumstances. High conversion efficiency and broad-scope chemoselectivity are driven by multiple plasmon-derived effects in AuPd nanoalloys, including electron enrichment, interfacial charge heterogeneity, and efficient hot-carrier injection, which operate synergistically under visible-light excitation.