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)₃]²⁺ 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)₃]²⁺, showing a promising platform for high-performance photocatalytic CO₂ conversion.