Abstract: The CeO2-Al2O3 composite support was prepared by the coprecipitation method with a mixed Al-(NO3)3-Ce(NO3)3 aqueous solution dropping into a mixed NH4HCO3-NH3·H2O aqueous solution. The Cu/La/CeO2-Al2O3 catalyst was prepared by impregnation of CeO2-Al2O3 with promoter La and active component Cu aqueous solution. The catalytic activity of the catalyst for the selective reduction of NO with propylene in excess oxygen was investigated. The relationship between the catalytic activity and the structure of the catalyst was also explored by means of scanning electron microscopy, atomic force microscopy,X-raydiffraction, surface area measurement, infrared spectroscopy, thermogravimetry,X-rayphotoelectron spectroscopy, and temperature-programmed reduction. The CeO2-Al2O3 could remarkably enlarge the catalyst surface area and pore size, increase the amount of Lewis acidity, and enhance the reducibility. The La promoter could further enlarge the catalyst surface area and pore size and increase the amount of Brnsted acidity and the thermal stability. Consequently, the catalyst exhibited higher activity for the selective reduction of NO with propylene in excess oxygen. The NO conversion decreased slightly even in the presence of water vapor.

Key words: copper, lanthanum, cerium dioxide, alumina, propylene, selective reduction, nitric oxide