Electrocatalytic reduction of CO2 to ethylene and ethanol through hydrogen-assisted C–C coupling over fluorine-modified copper

Electrocatalytic reduction of CO 2 into multicarbon (C 2+ ) products is a highly attractive route for CO 2 utilization; however, the yield of C 2+ products remains low because of the limited C 2+ selectivity at high CO 2 conversion rates. Here we report a fluorine-modified copper catalyst that exhibits an ultrahigh current density of 1.6 A cm −2 with a C 2+ (mainly ethylene and ethanol) Faradaic efficiency of 80% for electrocatalytic CO 2 reduction in a flow cell. The C 2– 4 selectivity reaches 85.8% at a single-pass yield of 16.5%. We show a hydrogen-assisted C–C coupling mechanism between adsorbed CHO intermediates for C 2+ formation. Fluorine enhances water activation, CO adsorption and hydrogenation of adsorbed CO to CHO intermediate that can readily undergo coupling. Our findings offer an opportunity to design highly active and selective CO 2 electroreduction catalysts with potential for practical application. Electrocatalytic reduction of CO 2 into multicarbon (C 2+ ) products is a highly attractive route for CO 2 utilization. Now, a fluorine-modified copper catalyst is shown to achieve current densities of 1.6 A cm −2 with a C 2+ Faradaic efficiency of 80% for electrocatalytic CO 2 reduction in a flow cell.