Polymeric ionic liquid promotes acidic electrocatalytic CO2 conversion to multicarbon products with ampere level current on Cu

The acidic electroreduction of CO2 into multicarbon (C2+) products is much attractive for the improved carbon utilization than alkaline or neutral electroreduction. How to improve the efficiency of C2+ products generation by acidic electroreduction of CO2, is important, especially at high current density and in electrolyte with low K+ concentration. Herein, we propose a strategy of capping Cu surface with a polymeric ionic liquid (PIL) adlayer for boosting the acidic electrocatalytic CO2 conversion to C2+ products at high current densities (ampere-level) and low K+ concentration. In the electrolyte with a relatively low K+ concentration (1.0 M), the Faradaic efficiency (FE) for C2+ products reaches 82.2% under a current density 1.0 A·cm−2 in acidic environment (pH=1.8). Particularly, when the current density is as high as 1.5 A·cm−2, the C2+ FE still keeps 75.8%. Experimental and theoretical studies reveal that the presence of PIL adlayer on Cu catalyst can well inhibit H+ diffusion to catalyst surface, enrich more K+ and facilitate C-C coupling reaction. Acidic electrocatalytic CO2 reduction is a promising way for CO2 utilization, of which the selectivity and activity need improvement. Here, the authors report polymeric ionic liquid can boost the acidic electrocatalytic CO2 reduction into multicarbon products on Cu at ampere level current density.