Alloy Nanoclusters Steering Enhanced Solar Water Oxidation

Metal nanoclusters (NCs) are characterized by discrete energy band structures, enriched catalytic active sites, and quantum confinement effects, rendering them a promising generation of light-harvesting antennas. Despite the advantages of exploring metal NCs-mediated photocatalytic systems, homometallic NCs inevitably suffer from ultrashort charge lifetimes, poor photostability, and difficulty in finely tuning spatially vectorial charge transfer. Heterogeneous metal doping, by introducing foreign atoms into metal NCs, represents a promising strategy to surmount these challenges. Herein, bimetallic Au_1-xNi_x alloy NCs are prepared for the first time via a green wet-chemistry method and serve as photosensitizers for steering photoelectrochemical (PEC) water-splitting reactions. The results ascertain that Ni atom doping over Au_x NCs substantially increases charge transport kinetics, enhances charge separation, and prolongs carrier lifetimes, resulting in significantly enhanced and stable PEC water oxidation activities under both simulated solar and visible light. Furthermore, the photoelectrochemical mechanism especially charge transfer characteristics is elucidated. Our work offers cutting-edge insights for the strategic mediation of photoinduced carrier flow over metal NCs toward solar energy conversion.