Cu dopant triggered Fe-N-C catalysts toward high efficiency electroreduction of CO₂ to CO

Electrochemical CO₂ reduction reaction (CO₂RR) is a promising approach to converting CO₂ to added value chemicals using renewable electricity. Herein, Fe/Cu-N-C catalyst is prepared by introducing copper source as a promoter into the mixture of iron source, carbon source, followed by pyrolysis. The obtained catalyst with curled edges flaky morphology and two kinds of Fe-containing sites, shows excellent CO₂RR performance. The catalyst exhibits above 90 % CO Faradaic efficiency (FE_CO) in a wide potential window from − 0.5 to − 0.7 V (92.4 % at −0.6 V), and FE_CO remained nearly unchanged after 10 h of electrolysis, revealing remarkable stability. According to calculations using density functional theory (DFT), the Fe/Cu-N-C catalyst's excellent catalytic performance can be attributed to the creation of Fe-Cu sites by adding Cu to the Fe-N-C structure. This could effectively lower the energy obstructions for the formation of COOH* intermediate and regulate the d-band states of the Fe atom.