Enhanced electrocatalytic CO2 reduction to methane via synergistic Sb and F dual-doping on copper foil under pulsed potential electrolysis

The electrocatalytic reduction of carbon dioxide (CO2) to methane (CH4) represents a promising strategy for carbon utilization, however, achieving high selectivity and efficiency remains a significant challenge. Herein, a copper foil-based catalyst with abundant interfaces was synthesized through electrodeposition to achieve Sb and F dual doping on the copper surface (CuSbF-ED), enabling efficient methane production through pulsed CO2 electrolysis. Under the pulsed electrolysis condition, the CuSbF-ED catalyst achieved a remarkably high CH4 Faradaic efficiency of approximately 92.6% and a partial current density of 60.3 mA•cm-2 at an overpotential of -1.2 V vs RHE, representing significant advancement over the static electrolysis performance of pristine copper foil. The in situ infrared spectroscopy results revealed an enhanced coverage of key intermediates *CHO on the CuSbF-ED surface during pulsed electrolysis. Theoretical calculations further confirmed that the CuSbF-ED structure with Sb and F dual doping stabilizes *CO intermediates and promotes the formation and adsorption of *CHO intermediates. Under the pulsed electrolysis conditions, the stabilized Cu species on CuSbF-ED surface facilitate the further conversion of adsorbed *CHO and *CH2O intermediates by deep hydrogenation processes toward high CH4 selectivity. The present research highlights Sb-F dual doping combined with pulsed potential electrolysis as a promising approach for the efficient and selective electroreduction of CO2 to CH4, contributing to sustainable carbon management