Mulberry-like hierarchical ZSM-5 zeolite supported MnSmOx catalysts for catalytic oxidation of propane

Hierarchical ZSM-5 zeolites were synthesized through a pre-aging treatment approach and employed as supports for the loading of MnSmO_x composite oxides. The pre-aging temperature makes significant effects on the physicochemical properties and catalytic activities for propane oxidation over the resultant catalysts. Specially, MnSm/HZ5/100 possesses notable mulberry-like morphology with micro-meso hierarchical porosity, which gives rise to the higher specific surface area, the better low-temperature reducibility and the more abundant surface active oxygen species comparable to the other catalytic systems. These superiorities are considered as the crucial parameters for its optimum catalytic activity, sufficiently high catalytic stability and water resistant ability under complex reaction conditions. In situ DRIFTs analysis reveals the primary reaction pathways of catalytic propane oxidation, where enolate and acetate species are identified as the key organic intermediates in the reaction. The participation of gas-phase oxygen can promote the further oxidation of organic intermediates.