Balance between Reducibility and N2O Adsorption Capacity for the N2O Decomposition: CuxCoy Catalysts as an Example.

CuxCoy (CuO-Co3O4 mixed oxides) catalysts were prepared via co-precipitation for the N2O decomposition reaction. They exhibited a higher N2O decomposition activity than that of pure CuO and Co3O4 because of the balance of the redox property and N2O adsorption capacity. Co3O4 presented a large number of surface oxygen vacancies, increasing the N2O chemical adsorption as "□-Co-ON2" on the catalyst surface, whereas CuO was dispersed around Co3O4 and presented high reducibility on the interface of Co3O4-CuOx for the N-O break of N2O, healing oxygen vacancies by leaving one oxygen atom in the vacancy. Based on kinetic studies, the rate constant of N2O decomposition was related to the number of surface vacancy sites ([Mn+]) and the rate of N-O break (k3), whereas the rate-determining step is the N-O break. Therefore, the N2O decomposition rate is first order to the N2O concentration. Overall, both the density functional theory calculations and kinetic results indicate that the quantities of adsorption and activation sites derived from the interaction between Co and Cu (dual-function mechanism) were accounted for the excellent N2O decomposition performance of CuxCoy catalysts.