Nanocrystalline Mixed Oxides Containing Magnesium Prepared by a Combined Sol-Gel and Self-Combustion Method for Catalyst Applications

Abstract

MgFe 2 O 4 spinel ferrite and La 0.6 Pb 0.2 Mg 0.2 MnO 3 perovskite nanopowders were synthesized by a combined sol-gel and self-combustion method and heat treatment. The morphological and structural characterization of the obtained powders has been performed with various techniques: X-ray diffraction (XRD), SEM observations, EDAX spectroscopy and BET analysis. The samples have been catalytically tested in flameless combustion reaction of acetone, benzene, pro-pane and Pb free gasoline at atmospheric pressure. The results revealed a higher catalytic activity of La 0.6 Pb 0.2 Mg 0.2 MnO 3 perovskite than that of MgFe 2 O 4 ferrite. This higher catalytic activity can be ascribed to smaller crystallite size (27 nm), larger surface area (8.5 m 2 /g) and the presence of manganese cations with variable valence (Mn 3+ -Mn 4+). The current results suggest that La 0.6 Pb 0.2 Mg 0.2 MnO 3 perovskite is preferable to the Mg ferrite and that it can be a promising catalyst for acetone and propane combustion at low temperatures.