SURFACE CHARACTERIZATION AND CATALYTIC PROPERTIES OF LA(1-X)A(X)MO(3)PEROVSKITE-TYPE OXIDES .1. STUDIES ON LA(0.95)BA(0.05)MO(3) (M-NUMBER-MN, FE OR CO) OXIDES

Perovskite type La(0.95)Ba(0.05)MO(3) (M = Mn, Fe or Co) oxides were p repared by a liquid precursor method and characterized by X-ray diffra ction, oxygen desorption, and X-ray photoelectron spectroscopic studie s. XPS analysis revealed the characteristic changes of the O1s peak (s imilar to 530 eV) resulting from the substitution of Ba in LaMO(3). Th e methane deep oxidation reaction was carried out in a plug flow react or with 2% CH4 in air in the temperature range of 200 to 700 degrees C . Among the three compounds, the Mn perovskite showed the lowest tempe rature for the methane conversion with a maximum at 700 degrees C. Tem perature programmed desorption (TPD) experiments also indicated the ma ximum oxygen desorption for Mn perovskite in this temperature range. T he results for oxygen chemisorption and surface area of these samples were found to be consistent with the observed variations in the cataly tic oxidation of methane.