Effect of catalyst composition and preparation conditions on catalytic properties of unsupported manganese oxides for benzene oxidation with ozone

Autor: Hisahiro Einaga, Nanako Maeda, Yasutake Teraoka
Rok vydání: 2013
Předmět:
Zdroj: Applied Catalysis B: Environmental. :406-413
ISSN: 0926-3373
DOI: 10.1016/j.apcatb.2013.05.041
Popis: Catalytic oxidation of benzene in gas phase with ozone was carried out at 70 °C over manganese oxides and manganese-based mixed oxides to investigate the effect of catalyst composition and preparation conditions on their catalytic properties. The oxides were prepared by an evaporation-to-dryness method and a co-precipitation method from metal nitrate precursors, followed by calcination at 400–900 °C. As for manganese monoxides, benzene oxidation rate normalized by catalyst surface area, product distribution and ozone/benzene decomposition ratio were almost independent of the preparation method and calcination temperature. Perovskite-type mixed oxides, LaMnO3 and La0.8Sr0.2MnO3 showed much lower activity and lower efficiency for ozone utilization in benzene oxidation than manganese monoxide and La sites promoted the accumulation of less-reactive byproduct compounds on the catalysts. In the case of manganese-based mixed oxides that contained Fe, Co, Ni, and Cu, benzene oxidation activity, CO2 selectivity and ozone/benzene decomposition ratio depended on the catalyst composition and preparation conditions. Among the mixed oxide catalysts, the Co–Mn mixed oxide prepared by the evaporation-to dryness method and calcined at 400 °C was the most effective for benzene oxidation from the standpoint of CO2 selectivity and efficiency for ozone utilization.
Databáze: OpenAIRE