Copper-Cerium Oxide Catalysts for CO Oxidation : An EXAFS and XRD Study

Mixed copper-cerium oxides were prepared by two methods leading to different wpper species in the as-prepared material. At the catalyst operating temperature (300400°C) and above, the same copper species was present irrespective of the prepration technique. A solid solution having the same fluorite structure as that of pure CeQ was formed and remained stable after calcination to 100O0C. At temperatures in excess of 600°C the formation of a CuO phase was also noticed. Catalytic activity of the mixed wpper-cerium oxides for the oxidation of CO to CQ proved very favourable even under 02 poor conditions. Activity decreased with in-ing calcination temperature as the material sintered and lost surface area, and the copper species deactivated through formation of CuO. The impoltance of EXAFS as an analytical tool in ascertaining the nature ofthe copper species at the catalyst operating temperature was Wghted.