A DFT study on the role of oxygen vacancy on m-ZrO2 (111) in adsorption and dissociation of CO2

The performance stability of a Catalytic Dry Reforming of Methane (CDRM) catalyst is primarily determined by its ability to resist coke formation. This is possible through removal of carbon deposited on the hydrogen production sites of the catalyst by mobile surface oxygen formed via CO2 dissociation. In this study, it is aimed to understand the role of oxygen vacancies in activation and dissociation of CO2 molecule on m-ZrO2, which has been widely studied as the support of CDRM catalysts. For this purpose, first, oxygen vacancy formation on mZrO2 (111) surface was investigated. Two possible types of oxygen vacancies were determined based on the results of periodic DFT calculations. Then, CO2 adsorption onto both stoichiometric and nonstoichiometric mZrO2 (111) surfaces were performed. The results revealed that the CO2 dissociation is possible only on the nonstoichiometric m-ZrO2 surfaces, and that presence of an oxygen vacancy, regardless of its type, significantly lowers the adsorption energy and increases adsorbate-metal oxide interaction. The study presented here theoretically proves at atomic scale that oxygen vacancies have a great influence on the dissociative CO2 adsorption ability of m-ZrO2, and confirms its clear potential as a support to be used in technical CDRM catalysts prepared for practical applications.