Optimizing *CO/CO Supply by Atomically Dispersed Fe Sites for High‐rate CO ₂ ‐to‐C ₂ H ₄ Conversion Under Visible Light

Visible light driven carbon dioxide (CO₂) reduction to ethylene (C₂H₄) is a promising pathway to obtain renewable fuels and valuable chemicals. However, the insufficient supply of *CO/CO severely limits the rate of C-C coupling toward C₂H₄. Herein, we present a synergistic engineering strategy to construct a Fe_0.2/H-MOF-1 composite catalyst by anchoring high-density iron single atoms sites (Fe SAs) onto a pyridinic nitrogen rich metal-organic framework (H-MOF-1). Under visible light, the catalyst achieves an exceptional C₂H₄ yield of 1056.2 µmol·g^-1·h^-1. This performance surpasses state-of-the-art systems for visible light driven CO₂-to-C₂H₄. The X-ray absorption fine structure (XAFS) analysis, CO adsorption experiments and density functional theory (DFT) calculations demonstrate that the Fe-N active sites in the Fe_0.2/H-MOF-1 catalyst not only significantly reduce the energy barrier from *COOH to *CO but also maintain abundant *CO/CO for C-C coupling through strong CO adsorption, thus efficiently promoting the rapid generation of C₂H₄. This study provides insights into the rapid generation of C₂H₄ through photocatalytic CO₂ reduction, paving the way for visible light-driven CO₂ reduction reactions.