Mesoporous manganese oxide nanoparticles for the catalytic total oxidation of toluene

Abstract

Mesoporous manganese oxide nanoparticles with the phases of tetragonal hausmannite, mixture of hausmannite Mn3O4 and monoclinic Mn5O8, and bixbyite Mn2O3 have been prepared by calcination of manganese acetate hydrate precursor at 200, 300, 400 and 700 °C, all of which were found to be active for the catalytic total oxidation of toluene. Their catalytic behavior depended on the oxidation state of manganese, the oxygen mobility and the amount of surface adsorbed oxygen species. The mesoporous nanoparticles calcined at 400 °C exhibited the highest catalytic performance with the complete toluene conversion temperature of 275 °C, suggesting that incorporating Mn5O8 into Mn3O4 could promote oxygen mobility, increase the amount of surface adsorbed oxygen and facilitate the activation of surface oxygen for the oxidation of toluene.