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‐Co3O4 (x=Na, K, Rb, Cs) catalysts for the N2O 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‐Co3O4 catalyst for N2O catalytic decomposition at low temperatures. By contrast, the deposition of other alkali metals (K, Rb and Cs) suppressed the catalytic decomposition of N2O perceptibly. Analysis of the results of XRD, FT‐IR, SEM, TEM, XPS, O2‐TPD and H2‐TPR characterization of x‐Co3O4 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‐Co3O4 catalyst, where the deposition of alkali metal Na not only facilitated the reduction of Co3+ to Co2+, but also promoted the surface decomposition step of N2O (i. e., the oxidation of Co2+ to Co3+ 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‐Co3O4 catalyst for the DCD of N2O 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.

An efficient biosensor using a functionalized microneedle of Cu2O-based CoCu-LDH for glucose detection

“…In addition, the weak absorption peaks below 800 cm −1 could be related to the stretching and bending vibrations of metal–oxygen bonds. 52,53…”

“…In addition, the weak absorption peaks below 800 cm −1 could be related to the stretching and bending vibrations of metal-oxygen bonds. 52,53 To better characterize the composition and crystallinity, the surface layer of CoCu-LDH/Cu 2 O was peeled off by ultrasonic treatment and subjected to the TEM measurement (Fig. 3A and B), in which the microstructure of CoCu-LDH nanosheet was much more distinct than that provided by FE-SEM.…”

Effect of alkali/alkaline-earth-metal doping on the Co3O4 spinel structure and N2O decomposition

“…There are precedents in the study of alkali/ alkaline-earth-metal doped Co 3 O 4 catalysts for N 2 O decomposition. [19][20][21][22] However, their analyses on the impact of alkali/alkaline-earth metals on the underlying mechanisms and the corresponding performances represent only a tip of the iceberg. Additionally, the reported performances of the literature catalysts may still be necessary for further improvement, potentially constrained by the advanced synthetic methods.…”