Enhanced performance of oxygen vacancies on CO 2 adsorption and activation over different phases of ZrO 2

The effect of oxygen vacancies on the adsorption and activation of CO 2 on the surface of different phases of ZrO 2 is investigated by density functional theory (DFT) calculations. The calculations show that the oxygen vacancies contribute greatly to both the adsorption and activation of CO 2 . The adsorption energy of CO 2 on the c-ZrO 2 , t-ZrO 2 and, m-ZrO 2 surfaces is enhanced to 5, 4, and 3 folds with the help of oxygen vacancies, respectively. Moreover, the energy barrier of CO 2 dissociation on the defective surfaces of c-ZrO 2 , t-ZrO 2 , and m-ZrO 2 is reduced to 1/2, 1/4, and 1/5 of the perfect surface with the assistance of oxygen vacancies. Furthermore, the activation of CO 2 on the ZrO 2 surface where oxygen vacancies are present, and changes from an endothermic reaction to an exothermic reaction. This finding demonstrates that the presence of oxygen vacancies promotes the activation of CO 2 both kinetically and thermodynamically. These results could provide guidance for the high-efficient utilization of CO 2 at an atomic scale.