Steric effects of CN vacancies for boosting CO2 electroreduction to CO with ultrahigh selectivity

In the electrochemical reduction of CO2 to CO, controlling the binding of the *COOH intermediate is key to adjusting the selectivity and catalytic activity of the CO product. Herein, we report that CN vacancies were used to control the binding of the *COOH intermediate on a Co PBA-V-CN catalyst treated by H-2 cold plasma bombardment to improve the CO2RR into CO. The CN vacancies can tune the local electronic structure and coordination environment of Co-III-CN-Co-II (Co-PBA-V-CN) with a high CO faradaic efficiency close to 100% with remarkable durability (>87 h), and a low onset overpotential of 0.17 V in CO2RR. The steric effects of the V-CN can decrease the free energy barrier of the rate limiting step for the formation of *COOH which can further crack into *CO on the active site of the Co near the V-CN. This work provides a new strategy to tune the binding of the *COOH intermediate on the catalyst surface by new vacancies of V-CN to enhance the CO2RR into a single product.

Automated summary

In this study, a new strategy to control CO2 reduction to CO by using CN vacancies is reported. It is found that CN vacancies can tune the local electronic structure and coordination environment of the catalyst, resulting in improved selectivity and catalytic activity for CO production. Additionally, the V-CN vacancies can lower the energy barrier for the formation of active sites, promoting the generation of *CO. This work provides a new approach for enhancing the CO2 reduction reaction.