Pt₁Bi Single-Atom Alloy for a Coupled Photocatalytic CO₂ Reduction and Aryl Olefin Oxidation System

Solar-driven CO₂ reduction provides a promising strategy to produce fuels and value-added chemicals, while the efficiency and economy of the system are often limited by the coupled oxidation half-reaction. Here, we develop a synergistic system coupling photocatalytic CO₂ reduction to CO and aryl olefin oxidation to aryl ketone with a high-efficiency and improved atom economy over a TiO_x-supported Pt₁Bi single-atom alloy photocatalyst. Combined experimental and computational studies elucidate the spontaneous electron transfer from Bi to Pt in the dark, which is enhanced under light radiation. Density functional theory calculations reveal that the oxidation process of aryl olefin favors the protonation of CO₂ and the dissociation of COOH* to CO*, and Bi facilitates CO₂ protonation and CO desorption on the Pt site. The generation rate of CO reaches 391 μmol g^-1 h^-1 with an electron selectivity of 91.4% using alpha-methylstyrene as the substrate, and the yield of the acetophenone product is 449 μmol g^-1 h^-1 with a 95.5% selectivity.