N/O Co-Coordinated Cu Active Sites in Metal-Organic Framework for the Electrochemical Reduction CO₂ to C₂₊ Products

Metal-organic frameworks (MOFs) are promising candidates for catalyzing the electrochemical CO₂ reduction reaction (CO₂RR) to alleviate environmental and energy issues. However, rationally designing active sites to enhance the adsorption of the key *CO intermediate for efficient CO₂-to-C₂₊ conversion remains a significant challenge. Herein, we propose a coordination atom regulating strategy to optimize the electronic structure of the Cu site for CO₂RR. A Cu-MOF (JXUST-304) featuring CuN₂O₂ active site (originating from CuN₂O₃ nodes removed of coordinated DMF) was constructed based on a ligand incorporating both pyridine N and -COOH groups. JXUST-304 displays superior catalytic performance in the CO₂-to-C₂₊ conversion with a Faraday efficiency of 64.7% alongside a partial current density of 129.1 mA cm^-2, surpassing similar Cu-MOF with CuN₄ active sites. The unique N/O co-coordination mode modulates the electronic structure to optimize the d-band center of Cu sites, which enhances the adsorption of *CO intermediate. Meanwhile, 3d_xz-2p_z π back bonding interaction reduces the formation energy barrier for *CHO to facilitate C-C coupling, resulting in a selective increase in C₂₊ products. This work offers insight into regulating the catalytic active sites within MOFs at the molecular level to promote the generation of targeted products.