Low-Coordination Single Au Atoms on Ultrathin ZnIn2S4 Nanosheets for Selective Photocatalytic CO2 Reduction towards CH4

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 (Au-1-S-2) on ultrathin ZnIn2S4 nanosheets was synthesized by a complex-exchange route, enabling exceptional photocatalytic CO2 reduction performance. Under visible light irradiation, Au-1/ZnIn2S4 catalyst exhibits a CH4 yield of 275 mu mol g(-1) h(-1) with a selectivity as high as 77 %. As revealed by detailed characterizations and density functional theory calculations, Au-1/ZnIn2S4 with Au-1-S-2 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.