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, 3dxz-2pz 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.