Surface characterization and catalytic properties of La1−A MO3 perovskite type oxides. Part I. Studies on La0.95Ba0.05MO3 (M = Mn, Fe or Co) oxides.

Perovskite type La0.95Ba0.05MO3 (M=Mn, FeorCo) oxides were prepared by a liquid precursor method and characterized by X-ray diffraction, oxygen desorption, and X-ray photoelectron spectroscopic studies. XPS analysis revealed the characteristic changes of the O1s peak (∼530 eV) resulting from the substitution of Ba in LaMO3. The methane deep oxidation reaction was carried out in a plug flow reactor with 2% CH4 in air in the temperature range of 200 to 700°C. Among the three compounds, the Mn perovskite showed the lowest temperature for the methane conversion with a maximum at 700°C. Temperature programmed desorption (TPD) experiments also indicated the maximum oxygen desorption for Mn perovskite in this temperature range. The results for oxygen chemisorption and surface area of these samples were found to be consistent with the observed variation in the catalytic oxidation of methane.