Synergistic Co single atoms and plasmonic Au nanoparticles for efficient photocatalytic CO₂ reduction

Addressing the intrinsic limitations of conventional single-active-site photocatalysts in charge separation and surface reaction kinetics, we reported a Co single-atoms/Au nanoparticles co-modified UiO-66 (Co₁-Au_NPs/UiO-66) for efficient CO₂-to-CO conversion. In a sacrificial-agent-free pure water system, Co₁-Au_NPs/UiO-66 delivered a remarkable CO evolution rate of 118.3 μmol g^-1 h^-1 with 96% selectivity, corresponding to 10.1- and 12.9-fold enhancements relative to Co₁/UiO-66 and Au_NPs/UiO-66, respectively. Systematic quasi-in-situ and in-situ spectroscopic analyses revealed that plasmonic Au nanoparticles acted as light-harvesting antennas to generate hot electrons, whereas isolated Co atoms functioned as catalytic electron acceptors. The distinctive Co₁-Au_NPs synergy enhanced the separation/transfer efficiency of photogenerated charge carriers and promoted the key *COOH intermediate formation. This work provides a novel paradigm for designing highly efficient artificial photosynthetic systems via multidimensional photoelectronic coupling.