Modulating the Asymmetric Atomic Interface of Copper Single Atoms for Efficient CO2 Electroreduction

Cu single-atom catalysts (Cu SACs) have been considered as promising catalysts for efficient electrocatalytic CO2 reduction reactions (ECRRs). However, the reports on Cu SACs with an asymmetric atomic interface to obtain CO are few. Herein, we rationally designed two Cu SACs with different asymmetric atomic interfaces to explore their catalytic performance. The catalyst of CuN3O/C delivers high ECRR selectivity with an FECO value of above 90% in a wide potential window from -0.5 to -0.9 V vs RHE (in particular, 96% at -0.8 V), while CuCO3/C delivers poor selectivity for CO production with a maximum FECO value of only 20.0% at -0.5 V vs RHE. Besides, CuN3O/C exhibited a large turnover frequency (TOF) up to 2782.6 h-1 at -0.9 V vs RHE, which is much better than the maximum 4.8 h-1 of CuCO3/C. Density functional theory (DFT) results demonstrate that the CuN3O site needs a lower Gibbs free energy than CuCO3 in the rate-determining step of CO desorption, leading to the outstanding performance of CuN3O/C on the process of ECRR-to-CO. This work provides an efficient strategy to improve the selectivity and activity of the ECRR via regulating asymmetric atomic interfaces of SACs by adjusting the coordination atoms.

Automated summary

This study explores the catalytic performance of two Cu single-atom catalysts (Cu SACs) with different asymmetric atomic interfaces. CuN3O/C catalyst exhibits high selectivity for electrocatalytic CO2 reduction to CO, with an FECO value of above 90% in a wide potential window. In contrast, CuCO3/C catalyst shows poor selectivity for CO production, with a maximum FECO value of only 20.0% at -0.5 V vs RHE. Additionally, CuN3O/C catalyst demonstrates a large turnover frequency (TOF) of 2782.6 h-1 at -0.9 V vs RHE, much higher than CuCO3/C catalyst with a maximum TOF of 4.8 h-1. Density functional theory (DFT) results reveal that the CuN3O site has a lower Gibbs free energy than CuCO3 in the rate-determining step of CO desorption, explaining the superior performance of CuN3O/C in CO production during electrocatalysis. This work provides an efficient strategy to enhance the selectivity and activity of electrocatalytic CO2 reduction reactions by regulating asymmetric atomic interfaces of Cu SACs.