Electrochemical reduction of CO2 to CO on bimetallic CoCu–N–C catalyst

Electrochemical reduction of CO 2 to valuable chemicals using electricity from renewable sources is a promising approach to realize the carbon cycle. Here, a novel bimetallic nitrogen-doped carbon catalyst (M-N-C, where M denotes the metal) CoCu–N–C electrocatalyst has been synthesized by pyrolyzing a copper-doped cobalt(II) acetate–phenanthroline complex formed from the metal acetates and 1,10-phenanthroline dissolved in ethanol. The optimal CoCu–N–C catalyst with molar ratio of Cu/(Co + Cu) = 0.15 displayed superior performance, enabling a faradaic efficiency of CO production of 76.5% at an overpotential of 0.57 V as well as an increased CO current density of 8.48 mA cm −2 at −0.98 V versus reversible hydrogen electrode (far superior than the Co–N–C of 4.20 mA cm −2 and Cu–N–C of 0.07 mA cm −2 ) and a decreased charge-transfer resistance compared with Co–N–C and Cu–N–C catalysts. The addition of Cu, which serves as a structure promoter to improve the dispersion of Co, thereby providing sufficient Co-N x active sites for the electrochemical CO 2 reduction reaction (CRR). Moreover, doping Cu changes the electronic environment around Co slightly and promotes the charge transfer capability so that reduces the energy barrier of potential-limiting energy, thereby improving the CRR performance of catalyst.