High-performance electroreduction CO₂ to formate at Bi/Nafion interface

Electrochemical CO₂ conversion into valuable products provides a promising solution for achieving a carbon-neutral energy cycle. Herein, an active and stable Bi/Nafion interface is fabricated over Bi nanosheets with the modification of Nafion, which exhibits superior CO₂ conversion with formate selectivity of above 95% in a wide potential range, partial current density of 72.12 mA cm⁻² at − 1.07 V vs. RHE in H-type cell. The extraordinary CO₂ reduction performance could be ascribed to a high CO₂ permeability and enhanced local proton activity at the Bi/Nafion interface, which leads to promoted CO₂ adsorption and feasible proton-coupled electron transfer during the CO₂ reduction process. Computational investigations reveal the modification of Nafion offers a comfortable platform to enable the key intermediate *OCHO to be stable. This work offers a valuable insight into interfacial manipulation of electrodes to convert CO₂ to valuable products.