CeO_2、TiO_2及Ce_(0.5)Ti_(0.5)O_2催化载体的制备及性能研究

Preparation and Properties of CeO_2,TiO_2 and Ce_(0.5)Ti_(0.5)O_2 Catalytic Carriers

采用热分解法、溶胶-凝胶法、沉淀法和水热法制备了CeO_2载体,SEM、XRD表征、N_2低温吸脱附和氢气程序升温还原(H2-TPR)实验和结果分析显示,溶胶-凝胶法制备样品具有更优的比表面积、孔容、孔径和氧化还原性能,故选择溶胶-凝胶法制备Ti_(0.5)Ce_(0.5)O_2混合氧化物催化载体。使用XRD、SEM、N2低温吸脱附、H2-TPR等分析手段对产物的物相特征、吸附性能和氧化还原性能进行了表征。Ti_(0.5)Ce_(0.5)O_2的H2-TPR在261、529和749℃处出现耗氢峰,分别归属于表面吸附氧的还原、表面晶格氧的还原和体相晶格氧的还原,TEM结果表明Ti4+离子进入CeO_2晶格形成TiO_2-CeO_2填隙固溶体,固溶体的形成有利于载体氧化还原能力的增强。

The CeO2 carriers were prepared by thermal decomposition,sol-gel,precipitation and hydrothermal methods.The results of XRD and SEM analysis,N2 adsorption-desorption isotherms and H2-temperature-programmed reduction(H2-TPR)patterns showed that the CeO2 particles obtained by sol-gel method possess good specific surface area,pore volume,pore diameter,and redox performance.Therefore,The mixed oxide catalyst carrier Ce0.5Ti0.5O2 was prepared by sol-gel method.The phase analysis,adsorption and redox properties of samples were investigated.The positions of hydrogen consumption peak of Ce0.5Ti0.5O2H2-TPR pattern were 261,529 and 749 ℃,attributed to adsorbed oxygen redox on the surface,lattice oxygen redox on the surface and the body phase lattice oxygen redox,respectively.The result of TEM showed that Ti^4+ entered into the CeO2 lattice and formed interstitial solid solution,it not only reduced the reduction temperature of CeO2 and TiO2,but also enhanced the redox property.