Structural and catalytic properties of mesoporous nanocrystalline mixed oxides containing magnesium

Abstract

Oxide compounds are promising catalysts for VOC flameless combustion. In this paper the catalyst properties of two Mg-containing oxide compounds with different crystalline structures and chemical compositions (Mg spinel ferrite and La–Pb–Mg–Mn–O perovskite) were investigated. The samples, prepared by a combined sol–gel and self-combustion method and heat treatment, were characterized using X-ray diffraction, scanning electron microscopy, EDAX spectroscopy, and BET analysis. The two samples have been catalytically tested in flameless combustion reaction of acetone, benzene and propane at atmospheric pressure. The results revealed a higher catalytic activity of the perovskite catalyst that may be ascribed to smaller crystallite size (26nm), larger surface specific area (8.6m2/g) and the presence of manganese cations with variable valence (Mn3+–Mn4+).