SURFACE CHARACTERIZATION AND CATALYTIC PROPERTIES OF PEROVSKITE-TYPE SOLID OXIDE SOLUTIONS, LA0.8SR0.2BO3( B=CR, MN, FE, CO OR Y)

The surface compositions of La0.8Sr0.2BO3 (B = Cr, Mn, Fe, Co or Y) we re investigated by X-ray photoelectron spectroscopy (XPS). Among the f ive solid oxide solutions, the yttrium showed the highest concentratio n in the surface atomic ratio [B-ion/(La + Sr)]. Furthermore, the Ols spectra characteristics of yttrium perovskite are found to be differen t from those of the other solid solutions with the peak shifted to hig her binding energy value. The electrical conductivity of La0.8Sr0.2CrO 3 and La0.8Sr0.2YO3 were also measured as a function of temperature in air. The E(sigma) values for conduction were found to be 0.12 and 0.7 2 eV respectively. The conductivity data correlated well with the cata lytic activity of these solid solutions for the oxidation of methane.