The Study Of Gold Caytalyst Over Nanostructural CeO₂Materials

CeO₂, for its unique redox properties and high oxygen storage capacity, has beenconsidered as an excellent support for Au catalysts. In present work, Au/CeO₂catalysts arepreapred by deposition precipitation method, the effect of CeO₂nanostucture and preparationparameters on the catalyst activity for CO oxidation are investigated. The main researchcontents are as follows:A study about the effect of preparation parameters on the catalyst performance:①Aseries of Au/CeO₂catalysts prepared by deposition precipitation using different concentrationof KOH, the results show that, the sample exhibited better activity when the alkali content isimproved.②A series of Au/CeO₂catalysts prepared with different Au loadings. It was foundthat the catalytic activity is not proportional with Au loadings.③A series of Au/CeO₂catalysts prepared at different calcination temperature. The sample prepared at the lowestcalcination temperature exhibited the best activity.④CeO₂-nanorods and CeO₂-nanocubeswere prepared by a hydrothermal method. Au nanoparticles are deposited on the surface ofthese CeO₂to obtain Au/CeO₂catalysts. The results showed the Au/CeO₂-nanorods exhibitbetter activity and stability than Au/CeO₂-nanocube.Hydrothermal synthesis method and precipitation method are used to obtain CeO₂nanorods, nanocubes, nanopolys, nanospheres and nanosparticles, respectively.Au/CeO₂-nanorods exhibited the highest catalytic activity for CO oxidation.Due to unique redox properties and high oxygen storage capability, highly stability andlow temperature catalytic activity, Ce-Zr mixed oxides are widely used in catalytic field. Thesupport of Ce-Zr-O solid solution with different ratio is prepared via hydrothermal synthesis,a series of Au/Ce-Zr-O catalysts are also prepared. It was found the Ce/Zr ratio shows stronginfluence on the catalytic activity in CO oxidation.Nanosized Au supported on Mn-Ce-O binary oxide were prepared by thedeposition-precipitation method. Various ratios of binary oxide supports are studied toinvestigate the effect of Au/Mn-Ce-O catalysts.The results exhibited that doped Mn species and Zr species could improve the stability ofcatalyst, but because of their inlet, weakening the interaction of cerium and noble metals, soaffecting the catalytic activity and selectivity.