Low‐Coordination Single Au Atoms on Ultrathin ZnIn2S4Nanosheets for Selective Photocatalytic CO2Reduction 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 (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.