Accelerated Photocatalytic Carbon Dioxide Reduction and Water Oxidation under Spatial Synergy

Abstract Photocatalytic conversion of CO 2 and H 2 O into fuels and oxygen is a highly promising solution for carbon‐neutral recycling. Traditionally, researchers have studied CO 2 reduction and H 2 O 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 ZnIn 2 S 4 ‐supported single‐atom Cu catalyst (Cu−SA/D−ZIS), which demonstrates remarkable catalytic performance with CO 2 reduction rates of 112.5 μmol g −1 h −1 and water oxidation rates of 52.3 μmol 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 ⋅⋅ V Zn “ defect complexes. FT‐IR studies coupled with theoretical calculations reveal the spatially synergistic CO 2 reduction and water oxidation on Cu Zn ′ V S ⋅⋅ 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 CO 2 reduction and H 2 O oxidation through a combination of experimental and theoretical analyses, providing a fresh insight in optimizing photocatalytic system.