CeO2-TiO2复合氧化物的制备、表征及其对CO氧化的催化性能

采用溶胶-凝胶法制备了一系列不同n(Ce)/n(Ti)的CeO2-TiO2复合氧化物,对复合氧化物的物相结构、形貌特征、比表面积和氧化还原性质进行了表征,并考察了复合氧化物对CO氧化反应的催化性能.结果表明,n(Ce)/n(Ti)>0.10时,复合氧化物为无定形结构;n(Ce)/n(Ti)=0.10~0.30时,复合氧化物失去CeO2和TiO2各自的特征,形成CeO2-TiO2固溶体,具有较大的比表面积.CeO2-TiO2复合氧化物本身对CO氧化反应的催化活性不如TiO2或CeO2的高,但Pd/CeO2-TiO2比Pd/TiO2或Pd/CeO2具有更高的催化活性.

Preparation and Characterization of CeO2-TiO2 Composite Oxide and Its Catalytic Performance for CO Oxidation

A series of CeO2-TiO2 composite oxide samples with different n(Ce)/n(Ti) were prepared by the sol-gel method.The phase structure,morphology,surface area,and redox properties of the composite oxide samples were investigated through N2 adsorption,X-ray diffraction,transmission electron microscopy,and temperature-programmed reduction,and their catalytic performance for CO oxidation was measured.The amorphous CeO2-TiO2 composite oxide was formed gradually when n(Ce)/n(Ti) was higher than 0.10.With n(Ce)/n(Ti) =0.10-0.30,the amorphous CeO2-TiO2 solid solution with high surface area was formed and exhibited the characteristics of neither CeO2 nor TiO2.Although CeO2-TiO2 had lower catalytic activity than either TiO2 or CeO2 for CO oxidation,the Pd/CeO2-TiO2 catalyst presented excellent performance for CO oxidation.