Low‐Coordination Single Au Atoms on Ultrathin ZnIn 2 S 4 Nanosheets for Selective Photocatalytic CO 2 Reduction towards CH 4

Selective CO2 photoreduction to hydrocarbon fuels such as CH4 is promising and sustainable for carbon-neutral future. However, lack of proper binding strengths with reaction intermediates makes it still a challenge for photocatalytic CO2 methanation with both high activity and selectivity. Here, low-coordination single Au atoms (Au1 -S2 ) on ultrathin ZnIn2 S4 nanosheets was synthesized by a complex-exchange route, enabling exceptional photocatalytic CO2 reduction performance. Under visible light irradiation, Au1 /ZnIn2 S4 catalyst exhibits a CH4 yield of 275 μmol g-1 h-1 with a selectivity as high as 77 %. As revealed by detailed characterizations and density functional theory calculations, Au1 /ZnIn2 S4 with Au1 -S2 structure not only display fast carrier transfer to underpin its superior activity, but also greatly reduce the energy barrier for protonation of *CO and stabilize the *CH3 intermediate, thereby leading to the selective CH4 generation from CO2 photoreduction.