Achieving High Single‐Pass Carbon Conversion Efficiencies in Durable CO2 Electroreduction in Strong Acids via Electrode Structure Engineering

Abstract

AbstractAcidic CO2 reduction (CO2R) holds promise for the synthesis of low‐carbon‐footprint chemicals using renewable electricity. However, the corrosion of catalysts in strong acids causes severe hydrogen evolution and rapid deterioration of CO2R performance. Here, by coating catalysts with an electrically nonconductive nanoporous SiC‐NafionTM layer, a near‐neutral pH was stabilized on catalyst surfaces, thereby protecting the catalysts against corrosion for durable CO2R in strong acids. Electrode microstructures played a critical role in regulating ion diffusion and stabilizing electrohydrodynamic flows near catalyst surfaces. This surface‐coating strategy was applied to three catalysts, SnBi, Ag, and Cu, and they exhibited high activity over extended CO2R operation in strong acids. Using a stratified SiC‐NafionTM/SnBi/polytetrafluoroethylene (PTFE) electrode, constant production of formic acid was achieved with a single‐pass carbon efficiency of >75 % and Faradaic efficiency of >90 % at 100 mA cm−2 over 125 h at pH 1.