Concentrating local protons through surface modification of Ag-based catalyst for direct (bi)carbonate electrolysis

Electrolysis of (bi)carbonates into valuable chemicals using renewable electricity is an attractive strategy to integrate CO 2 capture and valorization systems for reducing carbon emissions. Optimizing the proton concentration on the catalyst surface in (bi)carbonate electrolyzers can enable rapid local CO 2 release, making it a promising approach for enhancing electrocatalytic performance. This paper describes an efficient surface modification strategy using organic molecules with low p K a values to facilitate the accumulation of protons near the electrode. Operando Raman results prove that the modifier could promote pH swinging and increase the local CO 2 concentration. Consequently, when operated at a current density of 100 mA cm −2 , the acid-modified catalyst exhibited a CO Faradaic efficiency of 60%, higher than that of the base-modified catalyst, producing syngas with a CO/H 2 ratio of 0.5 at the cell voltage of 3.3 V. The proposed method offers promising new solutions for the development of commercially relevant integrated CO 2 reduction systems.