Promoting Effect of CeO2 on the Catalytic Activity of Ba–Y2O3 for Direct Decomposition of NO

Abstract

Abstract The effect of CeO2 additive on the catalytic performance of Ba–Y2O3 prepared by coprecipitaion for the direct decomposition of NO was investigated. Although Ba–Y2O3 effectively catalyzed NO decomposition, its activity was clearly increased by addition of CeO2. The optimum CeO2 content was 10 mol %. CO2-TPD measurement revealed that the addition of CeO2 into Ba–Y2O3 caused an increase in the CO2 desorption peak in the temperature range of 473 and 723 K derived from highly dispersed Ba species. The predominant role of CeO2 additive was suspected to effectively create the highly dispersed Ba species as catalytically active sites. Kinetic studies of NO decomposition on Ba–CeO2(10)–Y2O3 suggested that coexisting O2 suppresses the NO decomposition reaction by competitive adsorption. Isotopic transient kinetic analysis suggested a reaction pathway in which the surface NOx adspecies act as reaction intermediates for the formation of N2 in NO decomposition over Ba–CeO2–Y2O3. We concluded that CeO2 additive does not directly participate in the NO decomposition reaction as catalytically active species.