Facile synthesis of an antimony-doped Cu/Cu2O catalyst with robust CO production in a broad range of potentials for CO2 electrochemical reduction

Abstract

The electrocatalytic CO₂ reduction reaction (CO₂RR) on copper-based catalysts is a promising method to produce valuable chemicals, but its selectivity is much lower than expected largely due to insufficient research on the structure of new materials. Herein, the antimony-doped Cu/Cu₂O (Cu/Cu₂O–Sb) catalyst is developed for a highly selective CO₂RR to CO. The synthesized Cu/Cu₂O–Sb exhibits intensive suppression of hydrogen evolution, a low overpotential and high faradaic efficiency (FE) towards CO. The CO selectivity is as high as ∼95% with a partial current density of ∼6.3 mA cm⁻² at −0.9 V and maintains over 90% in a broad range of potentials. DFT calculations reveal that the doping of antimony achieves the distinct activation of CO₂ and suppression of hydrogen evolution. Meanwhile, the pre-adsorbed *CO significantly promotes the desorption of the neighboring *CO, which is the key for high selectivity of CO₂RR to CO. This work will provide a new consideration for the origin of high selectivity during the CO₂RR and pave the way toward design of highly selective CO₂ reduction catalysts.