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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 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‐S3, consequently giving rise to the CuZn′VS⋅⋅VZn" defect complexes. FT‐IR studies coupled with theoretical calculations reveal the spatially synergistic CO2 reduction and water oxidation on CuZn′VS⋅⋅VZn", 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. [ABSTRACT FROM AUTHOR]

High‐efficient photoelectrocatalytic direct ammonia oxidation reaction (AOR) conducted on semiconductor photoanodes remains a substantial challenge. Herein, we develop a strategy of simply introducing ppm levels of Cu ions (0.5–10 mg/L) into NH3 solutions to significantly improve the AOR photocurrent of bare BiVO4 photoanodes from 3.4 to 6.3 mA cm−2 at 1.23 VRHE, being close to the theoretical maximum photocurrent of BiVO4 (7.5 mA cm−2). The surface charge‐separation efficiency has reached 90 % under a low bias of 0.8 VRHE. This AOR exhibits a high Faradaic efficiency (FE) of 93.8 % with the water oxidation reaction (WOR) being greatly suppressed. N2 is the main AOR product with FEs of 71.1 % in aqueous solutions and FEs of 100 % in non‐aqueous solutions. Through mechanistic studies, we find that the formation of Cu−NH3 complexes possesses preferential adsorption on BiVO4 surfaces and efficiently competes with WOR. Meanwhile, the cooperation of BiVO4 surface effect and Cu‐induced coordination effect activates N−H bonds and accelerates the first rate‐limiting proton‐coupled electron transfer for AOR. This simple strategy is further extended to other photoanodes and electrocatalysts. [ABSTRACT FROM AUTHOR]

Herein we report the vital role of spin polarization in proton‐transfer‐mediated water oxidation over a magnetized catalyst. During the electrochemical oxygen evolution reaction (OER) over ferrimagnetic Fe3O4, the external magnetic field induced a remarkable increase in the OER current, however, this increment achieved in weakly alkaline pH (pH 9) was almost 20 times that under strongly alkaline conditions (pH 14). The results of the surface modification experiment and H/D kinetic isotope effect investigation confirm that, at weakly alkaline pH, during the nucleophilic attack of FeIV=O by molecular water, the magnetized Fe3O4 catalyst polarizes the spin states of the nucleophilic attacking intermediates. The spin‐enhanced singlet O−H cleavage and triplet O−O bonding occur synergistically, which promotes the O2 generation more significantly than the strongly alkaline case involving only spin‐enhanced O−O bonding. [ABSTRACT FROM AUTHOR]