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

Abstract

Purposefully designing the well-defined catalysts for the selective electroreduction of CO₂ to C₂ H₄ 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 C₂ H₄ . The highest faradaic efficiency of Cu₃ -X for CO₂ -to-C₂ H₄ 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 C₂ H₄ 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.

Keywords: CO2 reduction; C−C coupling; active sites; electrocatalysis; molecular catalysts.