Igand‐Mediated Enhancement of Cu(I) Concentration for Promoting CO₂ Electrocatalytic Conversion to Ethylene

Copper‐based complex molecular catalysts are highly tunable for electrocatalytic CO 2 RR products due to their controllable molecular structure. However, the role of the valence state of copper in the molecular catalysts in the electrocatalytic CO 2 RR reaction is not clear. In this work, for the first time, the electron‐donating effect of the ligand on the central Cu atom was enhanced by the addition of methyl groups to the bipyridine/phenanthroline ligand, which led to an increase in the central Cu(I) content and consequently in the ethylene content of the product. In situ electrochemical infrared spectroscopy and DFT theoretical calculations showed that during the reaction, the increased central Cu(I) content lowered the energy barrier for the conversion of 2*CO to *OCCO, thereby increasing the concentration of the *OCCO intermediate during the reaction. This method of controlling the valence state of the central atom by tuning the ligand structure of molecular catalysts to obtain different types of catalytic products provides a new idea for the design of new high performance molecular catalysts in the future.