Research On Preparation Of Mesoporous Ceria–Zirconia Solid Solution Materials And Application In Catalysis CO Oxidation And CO₂ Methanation At Low Temperature

With the development of social economy and the progress of science and technology,the environmental pollution caused by the annual increase of carbon monoxide and carbon dioxide emissions has become a serious problem facing the world,which also has a great impact on human health and living environment.Among the methods to solve this problem,catalytic transformation is considered to be the most effective method and has been widely used.Among many catalytic materials,mesoporous Ce-Zr solid solution catalysts have attracted extensive research and attention due to their regular channel structure,large specific surface area,good thermal stability,low price and direct use of catalytic reactions.In this paper,the mesoporous Ce-Zr solid solution catalysts with excellent catalytic performance and high stability are prepared by designing the strategies of doping metal elements.The main research contents are as follows:1.A series of mesoporous Ce-Zr solid solution materials are successfully synthesized by evaporation-induced self-assembly（EISA）and used as the carrier of CO catalytic oxidation catalysts.The catalytic properties of these Cu O-based catalysts are evaluated.The influence of Ce/Zr ratio,Cu O loading capacity and calcination temperature on the catalytic activity at low temperature is investigated.The results show that the catalytic activity of mesoporous Ce-Zr solid solution catalysts are much higher than that of Ce-Zr solid solution catalyst without obvious mesoporous structure,which indicates the advantages of mesoporous catalysts in the catalytic oxidation of CO.2.Cu O-based mesoporous Ce-Zr solid solution catalysts have the advantages of low cost,good catalytic activity and so on.In this study,a series of Cu O-based catalysts doped with metal oxides（La₂O₃,Fe₂O₃,Pr O₂,Sm₂O₃ and Mn O₂）are prepared using mesoporous Ce_0.8 Zr_0.2O₂ as the carrier.The mesoporous catalysts are systematically characterized.The Cu O and metal oxides are highly dispersed in the mesoporous skeleton,forming a strong metal skeleton interaction.The influence of dopant type and doping amount on the catalytic performance of CO at low temperature is studied.The results show that doped transition metal oxide can adjust the oxygen mobility and reduction ability of the catalyst,and further improve the catalytic activity of the catalyst.3.Bimetal doped Ni based mesoporous Ce_0.8Zr_0.2O₂ solid solution catalysts are prepared by co-impregnated and used for CO₂ methanation.Mesoporous bimetallic catalysts have higher catalytic activity and better coke resistance because of their bimetallic synergism.In addition,mesoporous structures can provide sufficient metal active centers for gaseous reactants and stabilize metal nanoparticles through the restriction of mesoporous skeletons,thus significantly improving catalytic performance.These catalysts have better catalytic performance and anticoke performance,providing a new catalyst choice for CO₂ methanation conversion.