Accelerated Photocatalytic Carbon Dioxide Reduction and Water Oxidation under Spatial Synergy

Photocatalytic conversion of CO2 and H2O into fuels and oxygen is a highly promising solution for carbon-neutral recycling. Traditionally, researchers have studied CO2 reduction and H2O oxidation separately, overlooking potential synergistic interplay between these processes. This study introduces an innovative approach, spatial synergy, which encourages synergistic progress by bringing the two half-reactions into atomic proximity. To facilitate this, we developed a defective ZnIn2S4-supported single-atom Cu catalyst (Cu-SA/D-ZIS), which demonstrates remarkable catalytic performance with CO2 reduction rates of 112.5 mu mol g(-1) h(-1) and water oxidation rates of 52.3 mu mol g(-1) h(-1), exhibiting a six-fold enhancement over D-ZIS. The structural characterization results indicated that the trapping effect of vacancy associates on single-atom copper led to the formation of an unsaturated coordination structure, Cu-S-3, consequently giving rise to the Cu-Zn ' V-S center dot center dot V-Zn" defect complexes. FT-IR studies coupled with theoretical calculations reveal the spatially synergistic CO2 reduction and water oxidation on Cu-Zn ' V-S center dot center dot V-Zn", where the breakage of O-H in water oxidation is synchronized with the formation of *COOH, significantly lowering the energy barrier. Notably, this study introduces and, for the first time, substantiates the spatial synergy effect in CO2 reduction and H2O oxidation through a combination of experimental and theoretical analyses, providing a fresh insight in optimizing photocatalytic system.