Predesign of Catalytically Active Sites via Stable Coordination Cluster Model System for Electroreduction of CO2 to Ethylene.

Purposefully designing the well-defined catalysts for the selective electroreduction of CO2 to C2H4 is an extremely important but challenging work. In this work, three crystalline trinuclear copper clusters (Cu3-X, X= Cl-, Br-, NO3-) have been designed, containing three active Cu sites with the identical coordination environment and appropriate spatial distance, delivering high selectivity for the electrocatalytic reduction of CO2 to C2H4. The highest faradaic efficiency of Cu3-X for CO2-to-C2H4 conversion can be adjusted from 31.90% to 55.01% by simply replacing the counter anions (NO3-, Cl-, Br-). The DFT calculation results verify that Cu3-X can facilitate the C-C coupling of identical *CHO intermediates, subsequently forming molecular symmetrical C2H4 product. This work provides an important molecular model system and a new design perspective for electroreduction of CO2 to C2 products with symmetrical molecular structure.