Surface-immobilized cross-linked cationic polyelectrolyte enables CO reduction with metal cation-free acidic electrolyte.

Electrochemical CO reduction in acidic electrolytes is a promising strategy to achieve high utilization efficiency of CO. Although alkali cations in acidic electrolytes play a vital role in suppressing hydrogen evolution and promoting CO reduction, they also cause precipitation of bicarbonate on the gas diffusion electrode (GDE), flooding of electrolyte through the GDE, and drift of the electrolyte pH. In this work, we realize the electroreduction of CO in a metal cation-free acidic electrolyte by covering the catalyst with cross-linked poly-diallyldimethylammonium chloride.