Covalently Tethering Atomically Precise Au25 Nanoclusters onto Covalent Organic Framework for Visible-light Driven CO2 Reduction

Solar-driven carbon dioxide (CO2) reduction can sustainably produce chemicals and fuels but is often limited by rapid charge recombination and slow CO2-to-product kinetics, typically necessitating homogeneous photosensitizers and cocatalysts. Here, we reported an integrated photocatalyst, TF-COF-CONH-Au25-Co, constructed by immobilizing atomically precise Au25 nanoclusters (NCs) on a covalent organic framework (COF) incorporating Co(bpy)32+ complex (Co-N6 coordination). Under visible-light illumination, this hybrid catalyzes CO2 conversion to syngas without external photosensitizers or cocatalysts, delivering a CO formation rate of 2,321.9 μmol·g-1·h-1 (turnover number of 171.9 and turnover frequency of 7.2 h-1). The Au25 NCs enhance light responsiveness and charge transfer efficiency, thereby enriching long-lived photogenerated electrons, while concurrently modulating the electronic state of Co sites to reduce the energy barrier for CO2 reduction. This study illustrates a molecular-level strategy to synergistically integrate metal NCs, COFs, and Co(bpy)32+, showing a promising platform for high-performance photocatalytic CO2 conversion.