Abstract: The cerium zirconium mixed oxides with high performance such as high surface area, good thermal stability were prepared by the method of co-precipitation and hydrothermal treatment. The stable crystal phase was formed under low temperature of 400 ℃, the surface area of fresh sample calcined at 500 ℃ is up to 135.44 m²/g, and the surface area of aged sample calcined at 900 ℃ for 6 h is 44.07 m ℃/g. The more thermal stable cerium zirconium mixed oxide powders were obtained by the process of co-deposition and hot aging, and by the technology of Al³⁺ doping modification, whose highest surface area of aged samples at 950 ℃ for 2 h is up to 59.62 m²/g. The superior mixed oxide is formed with the active alumina introduction into cerium zirconium mixed oxides, whose fresh surface area is 188.92 m²/g, aged sample at 950 ℃ for 4 h is 71.64 m²/g, and aged sample at 1 050 ℃ for 4 h is 58.10 m²/g. The mixed oxides was characterized by means of X-ray diffraction, adsorption and de-sorption. The cerium zirconium catalyst was obtained by palladium metal impregnation techniques. With methane catalytic combustion as probe reaction, the catalytic activity of cerium zirconium mixed oxides was studied, and the results show that cerium zirconium mixed oxides is a good carrier of support for combustion catalysts. The catalytic activity of palladium supported cerium zirconium catalyst is high, whose light-off temperature is as low as 352 ℃.

Key words: cerium zirconium mixed oxides; high surface area; good thermal stability; methane catalytic combustion