Plasmonic Charge Localization and C–H Activation at Single-Atom Sites in Dilute Copper Platinum Alloys

The role of energy transfer in plasmonic alloys is critical for advancing photocatalysis to industrially and societally relevant chemical processes. In this study, we synthesized and characterized CuPt dilute alloy catalysts to explore the impact of dopant concentration on energy transfer in plasmon-assisted nonoxidative propane dehydrogenation. By leveraging the localized surface plasmon resonance (LSPR) in copper nanoparticles, we examined how single-atom and ensemble Pt sites influence (photo)catalytic performance. <i>In situ</i> diffuse reflectance infrared Fourier transform spectroscopy, along with kinetic analysis of photocatalytic experiments, provided evidence that Pt single-atom sites enhance nonthermal charge carrier generation and energy transfer processes, accelerating C-H scission, resulting in a significant increase in light-driven reaction rates compared to CuPt alloys with ensemble Pt sites. The photochemical enhancement enabled by dilute plasmonic alloys is proposed to result from transient oxidative potentials (i.e., hot holes) localized on isolated dopant sites. These findings demonstrate the potential of engineering active sites in dilute plasmonic alloys for tailored electronic properties, paving the way for broader applications in plasmonic photocatalysis.