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

Abstract Visible light driven carbon dioxide (CO 2 ) reduction to ethylene (C 2 H 4 ) 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 C 2 H 4 . 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 C 2 H 4 yield of 1056.2 µmol·g −1 ·h −1 . This performance surpasses state‐of‐the‐art systems for visible light driven CO 2 ‐to‐C 2 H 4 . 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 C 2 H 4 . This study provides insights into the rapid generation of C 2 H 4 through photocatalytic CO 2 reduction, paving the way for visible light‐driven CO 2 reduction reactions.