Enhanced electrochemical reduction of CO2 to CO by ZnO nanorods enriched with oxygen vacancies

The efficiency of converting CO₂ to other valuable chemicals via the electrochemical reduction pathway depends on the electrocatalyst. In this work, an approach to prepare the ZnO catalysts used for the CO₂ electrocatalytic reduction was proposed, aiming at regulating the oxygen vacancy concentration in ZnO nanorods by changing the heat treatment temperature. The results show that the faradaic efficiency of CO₂ reduction to CO is significantly improved. An unprecedented faradaic efficiency of 98.3% and a current density of 786.56 mA cm⁻² were achieved using the ZnO catalyst heat treated at 500°C. It is revealed that the oxygen vacancy concentration, combined with density functional theory, can improve the performance of the ZnO electrocatalytic reduction of carbon dioxide (CO₂RR) by accelerating the activation of CO₂ molecules and reducing the energy barrier of CO formation. This work is helpful for the development of robust and efficient ZnO catalysts and their application in the CO₂RR.