铈锆固溶体的合成及其在CH4和CO催化燃烧反应中的应用

Synthesis of Ceria-Zirconia Solid Solutions and their Application in Catalytic Combustion Reaction of CH_4 and CO

分别利用固态反应和共沉淀法制备了铈锆固溶体,并以其为载体制备了车用三效催化剂,考察其在CH4和CO催化燃烧反应中的作用.研究发现固态反应法所得固溶体孔分布较宽,热稳定性较差,但表面较多的缺陷位贡献于其较高的储氧性能.而共沉淀法所得样品拥有较高的热稳定性和催化活性.固溶体的还原性质可以通过铈锆比调控.关联催化剂对CH4和CO的催化氧化性能发现,具有较大比表面积、集中孔径分布和较高储氧能力的固溶体显示了较低的催化剂起燃温度和较高的催化活性.

CeO-ZrO2 solid solutions were prepared by solid-state reaction and co-precipitation methods respectively and used as three-way exhaust catalyst support.The catalytic performance of the catalysts were investigated using CH4 and CO as probe molecules.The results showed that there were great difference in physical structure of products prepared with the different methods.The solid solutions prepared via solid-state reaction bear the broaden pore distribution and poor thermal stability.While the higher oxygen storage capacity can be exhibited owing to the more vacancies on the surface.The optimum thermal stability and higher catalytic activity can be shown for the samples prepared with co-precipitation method.The redox property of the solid solutions can be tuned by controlling of Ce/Zr ratio.The lower light-off temperature and higher conversion of methane and mono-oxygen carbon can be demonstrated for the catalysts with larger surface area,concentrate pore distribution and higher oxygen storage capacity.