Accelerated Photocatalytic Carbon Dioxide Reduction and Water Oxidation under Spatial Synergy.

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.