SYNTHESIS AND CHARACTERISTICS OF NONSTOICHIOMETRIC NANOCRYSTALLINE CERIUM OXIDE-BASED CATALYSTS

Nanocrystalline materials are associated with high surface area and re activity. Gas condensation techniques have been developed to synthesiz e such systems with a unique control of stoichiometry and dispersion. The high concentrations of oxygen vacancies and surface adsorbed speci es in nanocrystalline CeO2-x were found to greatly enhance catalytic a ctivity in SO2 reduction and CO oxidation. By having an ultrahigh disp ersion of Cu on nanocrystalline CeO2-x, we have further demonstrated t he possibility of tailoring intimate synergistic effects between diffe rent components in a nanocomposite material. The resulting supported b ase metal system has an unusually high thermal stability and could sel ectively catalyze SO2 reduction and CO oxidation at significantly lowe r temperatures (420 degrees C and 80 degrees C, respectively), The hig h redox activity of the nanocrystalline CeO2-x-based system is tied to the microstructure, surface chemistry, and electrical conductivity of this advanced catalyst.