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

摘要

MgFe2O4 spinel ferrite and La0.6Pb0.2Mg0.2MnO3 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, propane and Pb free gasoline at atmospheric pressure. The results revealed a higher catalytic activity of La0.6Pb0.2Mg0.2 MnO3 perovskite than that of MgFe2O4 ferrite. This higher catalytic activity can be ascribed to smaller crystallite size (27 nm), larger surface area (8.5 m2/g) and the presence of manganese cations with variable valence (Mn3+ - Mn4+). The current results suggest that La0.6Pb0.2Mg0.2MnO3 perovskite is preferable to the Mg ferrite and that it can be a promising catalyst for acetone and propane combustion at low temperatures.