Polymeric ionic liquid promotes acidic electrocatalytic CO(2) conversion to multicarbon products with ampere level current on Cu.

The acidic electroreduction of CO(2) into multicarbon (C(2+)) products is much attractive for the improved carbon utilization than alkaline or neutral electroreduction. How to improve the efficiency of C(2+) products generation by acidic electroreduction of CO(2), 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 CO(2) conversion to C(2+) 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 C(2+) 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 C(2+) 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.