Cerium-based Oxides Supported Nano Gold Catalytic Co Oxidation

As one of the major air pollutants, the oxidation of carbon monoxide has important practical significance for industry, environmental protection, military and every aspect of human life.In this paper, a serious of Au catalysts were prepared by deposition-precipitation (DP) and microwave irradiation (MWI) methods and tested in CO oxidation. The samples were characterized by XRD,BET,Raman,TPR,TEM measurements, and the results were related to the catalytic performance. For the part of DP method, the influence of preparation methods, optimization synthesis condition and the structures of the supports on the catalytic activities of the Au/Ce0.8Zr0.2O2 catalysts was investigated. The result indicated that the supports with high specific surface area and cubic structure could be prepared by sol-gel method with the addition of petroleum ether and surfactant. The oxygen vacancy and the specific surface area of the support were increased by the addition of Sr. Moreover, the effect of preparation factors such as Au loadings, calcination atmosphere, temperature and time on the catalytic activities was also discussed. Using this method, a series of Au/Ce0.8Zr0.2O2 catalysts with Au particle size of 3-7 nm were obtained under CO atmosphere at 400℃calcined for 3 h, which can oxidize CO completely at 45℃. The high catalytic activity of the catalysts could be attribute to the following two reasons:one is the strong interaction between the support and the Au particles, and the other is the well dispersion degree of Au nanoparticles.For the part of MWI method, the catalysts Au/Ce1-xZrxO2 were synthesized by one step for the first time. And the influence of microwave power, PEG incorporation, calcination temperature, the pattern of precipitation, Au loadings on the catalytic activity of the catalysts was also investigated. In the process of catalysis preparation, by addition of PEG as the microwave absorbent, deposition the Au particles by SP method, irradiation under the microwave and calcination, a uniform dispersion of Au nanoparticles with the size of 4.2nm was formed. And the catalytic activity was similar to the DP method. The results showed that the high specific surface area and well dispersion degree of Au nanoparticles on the support was responsible for the superior catalytic property. Compared with the DP method, the significance of the MWI method lies mainly in its simplicity, flexibility, shorter reaction time and environment friendly.