Switching the Symmetry of a Trinuclear Copper Cluster Catalyst for Electroreducing CO₂ to an Asymmetric C₂ Product in an Acidic Electrolyte

Achieving CO2 electroreduction in an acidic electrolyte to obtain high-value products is a great challenge, but it has remained elusive so far due to the high requirements for catalyst stability. Herein, we designed and constructed a highly stable (acid- and alkali-resistant) and well-defined crystalline coordination compound catalyst, Inz-Cu3, which can switch the structural symmetry by varying the distance and angle between the adjacent synergistic Cu active sites, thus achieving the selective conversion of CO2 to a high-value C2 product in an acidic electrolyte. At a current density of −320 mA·cm–2, it achieved up to 42.20% selectivity for the electrocatalytic reduction of CO2 to C2 products in an acidic electrolyte, and the highly selective catalytic conversion to C2 products (66.79%, containing 35.27% FEC2H4 and 31.52% FEC2H5OH) can also be achieved in a conventional alkaline electrolyte. Moreover, the density functional theory (DFT) calculation and control experiments revealed that the adjacent asymmetric Cu active sites with close distance can stabilize *CHOHCH3 intermediates, thus improving the selectivity of the asymmetric C2 product. This work demonstrates a strategy for the structural design of asymmetric crystalline coordination catalysts and enables the achievement of electroreduction conversion of CO2 to high-value-added C2 products in an acidic electrolyte.