High-energy mechanical synthesis of nanophase fluorite- structured mixed oxide catalysts with a high redox activity

摘要

A series of nanostructured, highly defective, ternary solid solutions containing CeO_2, ZrO_2, and mnO_2 or CuO were prepared by high-energy mechanical milling of individual components. Morphological and redox properties were studied by XRD, HRTEM and temperature-programmed reduction techniques. It was shown that the introduction of small amounts of copper and manganese strongly promotes the redox behaivor of cerium at lower temperatures in comparison promote overall redox capacity without affecting low-temperature redox behavior. Moreover, evidence is provided to show that Cu and Mn are dissolved within the CeO_2 lattice structure. Addition of dopants enhances catalytic redox properties in the oxidation of CO at low temperatures, which is associated with the high concentration of oxygen vacancies that form on the introduction of aliovalent elements into the ceria-zirconia lattice.