High-Energy Mechanical Synthesis of Nanophase Fluorite-Structured Mixed Oxide Catalysts with a High Redox Activity

Abstract

ABSTRACTA series of nanostructured, highly defective, ternary solid solutions containing CeO2, ZrO2, and MnO2 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 behavior of cerium at lower temperatures in comparison with CeO2 and CeO2-ZrO2. High temperature treatment of up to 1400K was also shown to further promote overall redox capacity without affecting low-temperature redox behavior. Moreover, evidence is provided to show that Cu and Mn are dissolved within the CeO2 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.