Synergistic Catalysis by Cu Single Atoms and Atomically Cu-Doped Au Nanoparticles in a Metal–Organic Framework for Photocatalytic CO 2 Reduction to C 2 H 6

Photocatalytic CO 2 reduction to C 2 hydrocarbons is considered more valuable and yet highly challenging due to the multielectron process and sluggish kinetics of C–C coupling, which requires multiple active sites to work synergistically. In this work, through a photodeposition method, Cu single-atom sites and atomically Cu-doped Au nanoparticles were simultaneously anchored on a photoactive metal–organic framework (MOF) with mesoporous channels, closely integrating distinct sites within a confined environment. Thanks to the electron accumulation of plasmonic metal nanoparticles and the synergy among different active sites, this MOF composite can achieve efficient photocatalytic reduction of CO 2 to C 2 H 6 with a production rate as high as 69.9 μmol g –1 h –1 and a selectivity as high as 71.1%. Photocatalytic experiments with control samples unveiled the critical roles of different active sites at each step, which was further confirmed by in situ characterizations and theoretical calculations. This finding highlights the potential of MOFs as an ideal platform for the integration of various active sites for synergistically catalytic applications.