Cesium promoted Co3O4 catalyst deposited on ceramic foam support for nitrous oxide decomposition

Abstract

Nitrous oxide is a significant pollutant. Large stationary sources of N2O emissions, such as nitric acid plants, are the most suitable for N2O emissions abatement. Direct N2O catalytic decomposition is a promising option for N2O abatement. Cs-doped Co3O4 is known to be active for N2O catalytic decomposition. Dispersion of the active components over a structured support surface may largely improve the applicability of the catalyst in industrial scale. Apart from the active components’ chemical composition, the resultant catalyst activity is influenced by the method of their deposition on the support as well.

In this work, the preparation of Co3O4 De-N2O catalyst on ceramic foam structured support by organic-assisted impregnation is investigated. Acetic acid, citric acid, glycerol, glycine and urea are tested as organic impregnation agents. The catalysts are characterized by AAS, BET, SEM, TPR-H2 and XRD. Using glycerol as the organic impregnation agent leads to the highest improvement of the catalyst De-N2O activity. Preparation of the catalyst by glycerol-assisted impregnation is further optimized. The optimal glycerol-to-cobalt molar ratio of the impregnation solution is found to be 1:1. The optimized glycerol-assisted impregnation method is used for preparation of Cs-doped Co3O4 catalysts on ceramic foams. Based on De-N2O catalytic tests in simulated nitric acid plant tail-gas (N2O, O2, H2O, NO, N2), the optimal Cs loading is found to be between 1.5 and 1.9 wt. % of Co3O4.