Enhanced Electrocatalytic CO₂ Conversion to CH₄ via Molecular Engineering on Copper Salphen Complexes

Abstract

Electrocatalytic reduction reaction of CO2 (CO2RR) enables a new paradigm toward carbon neutrality. Metal molecular complexes with well-defined active centers and easily tailorable structures are promising electrocatalysts for CO2RR. In this regard, copper salphen-based complexes are studied as electrocatalysts for CO2RR for the first time. The computational finding reveals that the optimized electronic structure of Cu active center is the key for good CO2RR performance, which is consistent with the experimental results. The optimized fluorine substituted in the 3,3′-position of copper salphen shows nearly 2-fold CO2 electrolytic activity and a much higher Faradaic efficiency of 62 ± 2% for CH4 production, compared with the commercial copper phthalocyanine. These results provide significant insights upon the rational design of metal complex catalysts through the regulation at molecular level toward efficient CO2 electrolysis.