AN IMPROVEMENT ON THE PREPARATION OF LA-SR-CO PEROVSKITE BY THE OXALATE METHOD

An improvement of the precipitation method using oxalic acid as the precipitant of perovskite catalysts is successfully undertaken. By substituting ethanol for distilled water in the washing of the perovskite precursors, the previous problems of chemical inhomogeneity and cobalt elution are minimized. The variously prepared perovskite-type oxides are physically characterized by X-ray diffraction, thermogravimetric analysis, infrared (IR), scanning electron microscopy, surface area, pore volume, pore size distribution, and oxygen adsorption measurements. Although the results reveal that all the physical properties of the prepared products differ from those from the potassium carbonate method, both kinds of perovskite-type oxides demonstrated high catalytic activity for oxidation of toluene. The IR spectra are helpful in judging whether or not perovskite-type oxides contain the La2O3 structure. The proposed method is both an easier and more rapid way of preparing a large amount of perovskites having higher surface area, pore volume, and activity.