Ni Single Atoms/Nanoparticles‐Decided Spatial Adjustment of Photocatalytic Redox Sites Boosting CO 2 Reduction in H 2 O Vapour

Abstract The kinetics matching of CO 2 reduction and H 2 O oxidation is required in sacrificial agent‐free photocatalytic CO 2 reduction. It indicates that the modification engineering on photocatalytic H 2 O oxidation half‐reaction except that on photocatalytic CO 2 reduction half‐reaction should be equally paid attention, which has been easily ignored in most of the literatures. Herein, Ni single atoms (NiSAs) and nanoparticles (NiNPs) co‐loaded Ti‐MOF‐derived TiO 2 having a flower‐like nanosphere microstructure (NiSAs@NPs/TC) was developed for synchronous design of well‐defined redox active sites of photocatalytic CO 2 reduction and H 2 O oxidation. It was verified that NiNPs and NiSAs as the active sites of CO 2 reduction and H 2 O oxidation, respectively, synergically accelerated photocatalytic redox reactions and enhanced separation of photo‐generated carriers. NiSAs@NPs/TC showed a remarkable photocatalytic CO 2 ‐reduction performance (CO and CH 4 products: 35.60 and 3.41 μmol g −1  h −1 , respectively) in H 2 O vapour which was at the advanced level in published relevant studies. Furthermore, the reaction process of CO 2 reduction on NiNPs was proposed based on the key intermediates capture of CO and CH 4 production in photocatalytic CO 2 reduction by in situ analysis.