Thermally stable lanthanum-doped mesoporous alumina as a stable support for palladium in catalytic oxidation of C3H8

High thermally stable mesoporous alumina doped with lanthanum was synthesized using inorganic nitrates as precursors and employing pluronic P123 (P123, (EO20PO70EO20, EO=ethylene oxide, PO=propylene oxide)) as a structure-directing agent. After calcination at 400 °C, the resultant lanthanum doped alumina exhibited a γ-Al2O3 phase, which was the same as pure alumina. After the thermal treatment up to 1200 °C, La-doped Al2O3 generated only one phase of θ-Al2O3 rather than two mixed phase of θ-Al2O3 and α-Al2O3 and the surface area could still maintain 101 m2/g with a keeping pore volume of 0.66 cm3/g. The excellent thermal stability was explained by the titration of strong Lewis acid sites of γ-Al2O3 with the assistance of highly dispersed lanthanum species covering on alumina. Furthermore, the lanthanum modified mesoporous alumina was preliminarily employed as a stable support for Pd in the catalytic oxidation of C3H8.