Structures and Properties of La0.8Sr0.2MnO3+σ-z SBA-15(z=0, 1, 2, 4) Perovskite Catalysts

Mesoporous LaSrMnO/z SBA-15(z = 1, 2, 4) perovskite oxides were synthesized via hard-templating with ordered mesoporous silica SBA-15 as the template. The as-prepared samples were characterized by XRD, SEM, AFM, BET, and XPS and the catalytic activity was tested for CO oxidation. The wide-angle XRD patterns showed that LaSrMnOperovskite was formed. The SEM and AFM analyses exhibited that LaSrMnOby hard-templating method had much smaller particle size(18 nm) than that(40 nm) by the sol-gel method. The perovskite-type oxides LaSrMnO/z SBA-15(z = 1, 2, 4) also displayed a higher BET surface area from 70 to 143.7 m~2/g and a disordered mesostructure from nitrogen sorption analysis, as well as a small-angle XRD pattern. Moreover, the LaSrMnO/z SBA-15(z = 1, 2, 4) perovskite exhibited a much higher activity in CO oxidation than the conventional LaSrMnOperovskite. Further analysis by the means of XPS techniques indicated that the existence of high content of O/Ospecies contributed to the high activity.