Abstract
Electrocatalytic CO2 reduction reaction(CO2RR)to produce multicarbon(C2+)products over Cu-based catalysts represents an ideal approach for renewable energy storage and carbon emissions reduction.The Cu0/Cuδ+interfaces are widely recognized as crucial sites that promote C-C coupling and enhance the generation of C2+products.However,a major challenge arises from the tendency of Cuδ+active sites within Cu0/Cuδ+interfaces to undergo reduction to Cu0 during the CO2RR process,leading to a decline in catalytic performance.Hence,it is crucial to establish durable Cu0/Cuδ+interfaces to enhance the conversion of CO2 to C2+products.In this work,an iodine modification strategy is proposed to prepare a stable Cu@CuI composite catalyst with well-maintained Cu0/Cuδ+interfaces through a one-step redox reaction between iodine and copper.The optimized Cu@CuI-3 composite catalyst demonstrates an excellent performance in CO2RR,achieving a Faradaic efficiency of 75.7％for C2+products and a partial current density of 288 mA·cm-2 at-1.57 VRHE in a flow cell.Operando techniques reveal that a numerous persistent Cuδ+species exist on the surface of the Cu@CuI-X composite catalyst even after CO2RR due to the presence of adsorbed iodine ions,which prevent complete reduction of Cuδ+species to Cu0 owing to their high electronegativity.Density functional theory calculations further verify that adsorbed iodine ions on the surface of Cu@CuI-X serve as charge regulators by adjusting local charge density,thereby facilitating the formation of*CHO intermediates from CO2 and lowering the energy barriers associated with coupling the*CHO and*CO intermediates during CO2RR.Consequently,this phenomenon enhances the selectivity toward C2+products during electrocatalytic CO2 reduction.
万方数据