Employing P123 as a structure directing agent and acetic acid as an interfacial protector, ordered mesoporous silicon-doped gamma-alumina with high thermal stability was synthesized through a modified sol-gel process by adding aluminum isopropoxide in batches to control the hydrolytic and condensation rate of Al3+. When the silicon content was 10-25 wt%, the specific surface area of the as-obtained samples were higher than others. Especially when the silicon content up to 20 wt%, the sample still maintained ordered mesoporous gamma-Al2O3 phase with a large specific surface area of 139.8 m(2) g(-1) and narrow pore size distribution even the calcination temperature up to 1100 degrees C. Taking as-synthesized ordered mesoporous alumina COMA) as carrier, the catalysts with high thermal stability supported by Pd were obtained by a facile process of thermal incipient wetness impregnation, which shows highly dispersed nano-particles and ordered mesostructure. When applied the catalysts in the catalytic converters of simulated exhaust automobile gases, it was found that the ordered mesostructure and high surface area showed significant effects in promoting catalytic activity. The as-synthesized ordered mesoporous Pd-alumina catalyst exhibited an excellent catalytic activity for gas mixture including CO, NO and hydrocarbon (HC). (C) 2016 Elsevier B.V. All rights reserved.