Unravelling the Effect of Alkali Metal Deposition on Co3O4 for Catalytic Decomposition of N2O

Abstract In this paper, the effect of alkali metal deposition on the activity of x‐Co 3 O 4 (x=Na, K, Rb, Cs) catalysts for the N 2 O catalytic decomposition was systematically explored by DFT calculation and various experimental characterization methods. The results demonstrated that the deposition of alkali metal Na improved the activity of the Na‐Co 3 O 4 catalyst for N 2 O catalytic decomposition at low temperatures. By contrast, the deposition of other alkali metals (K, Rb and Cs) suppressed the catalytic decomposition of N 2 O perceptibly. Analysis of the results of XRD, FT‐IR, SEM, TEM, XPS, O 2 ‐TPD and H 2 ‐TPR characterization of x‐Co 3 O 4 catalysts showed that the deposition of alkali metals did not affect the morphology and structure of the catalysts. However, it affected the chemical environment around the Co ion in the x‐Co 3 O 4 catalyst, where the deposition of alkali metal Na not only facilitated the reduction of Co 3+ to Co 2+ , but also promoted the surface decomposition step of N 2 O (i. e., the oxidation of Co 2+ to Co 3+ by giving electrons) at low temperatures, indicating that alkali metal Na improved the electron donating capability of the catalyst active center and enhanced the performance of the Na‐Co 3 O 4 catalyst for the DCD of N 2 O at low temperatures. The deposition of other alkali metals did not show the same results as that of alkali metal Na, indicating that the promotion of different alkali metals was different and would directly affect the catalytic effect. At low temperatures, the catalytic activity of catalysts deposited with the alkali metal Na was greater than that of catalysts deposited with other alkali metals.