Oxygen vacancy enhancing CO2 electrochemical reduction to CO on Ce-doped ZnO catalysts

Abstract

Oxygen vacancy defect engineering is currently an effective strategy to enhance the performance of electrocatalytic CO2 reduction to CO. In our work, ZnO with oxygen vacancies defects by Ce3+ doping were obtained through solvothermal method. The oxygen vacancies defects concentration could be controlled by varying the Ce3+ dopant concentration, which initially increased then decreased. And the CO2ER performance of as-prepared samples is found to be closely dependent with the concentration of oxygen vacancy in the as-prepared CexZn1-xO. The optimized CO2ER to CO performances can be obtained from Ce0.016Zn0.984O with the highest oxygen vacancy concentrations, which exhibited the highest performance (current density 24 mA cm−2 and Faradaic efficiency 88% for CO) at -1.0 V versus RHE. Through CO2 isotherm adsorption curve and CO2 temperature-programmed desorption (CO2-TPD) test, it was proved that the high concentration oxygen vacancy of Ce0.016Zn0.984O was beneficial to improve the CO2 adsorption and activation. This study proposes a strategy aimed at obtaining a high-performance catalyst for electrocatalytic CO2 reduction by adjusting the concentration of oxygen vacancies.