Catalytic Reaction Mechanism of NO–CO on the ZrO(2) (110) and (111) Surfaces

Due to the large population of vehicles, significant amounts of carbon monoxide (CO), nitrogen oxides (NO(x)), and unburned hydrocarbons (HC) are emitted into the atmosphere, causing serious pollution to the environment. The use of catalysis prevents the exhaust from entering the atmosphere. To better understand the catalytic mechanism, it is necessary to establish a detailed chemical reaction mechanism. In this study, the adsorption behaviors of CO and NO, the reaction of NO reduction with CO on the ZrO(2) (110) and (111) surfaces was performed through periodic density functional theory (DFT) calculations. The detailed mechanism for CO(2) and N(2) formation mainly involved two intermediates N(2)O complexes and NCO species. Moreover, the existence of oxygen vacancies was crucial for NO reduction reactions. From the calculated energy, it was found that the pathway involving NCO intermediate interaction occurring on the ZrO(2) (110) surface was most favorable. Gas phase N(2)O formation and dissociation were also considered in this study. The results indicated the role of reaction intermediates NCO and N(2)O in catalytic reactions, which could solve the key scientific problems and disputes existing in the current experiments.