Synthesis and characterization of CuO/Ce 1-x Ti x O2 catalysts used for low-temperature CO oxidation.

A series of CuO/Ce(1-x)Ti(x)O(2) catalysts used for low-temperature CO oxidation were prepared by impregnation with the support derived from surfactant-assisted co-precipitation. The techniques of N(2) adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by H(2) (H(2)-TPR) were employed for catalyst characterization. It is found that the support CeO(2) prepared by the surfactant-assisted method possesses much larger specific surface area than the one obtained from conventional precipitation. Doping Ti in the support with Ti/Ce atomic ratio of 1:9 or 3:7 can further increase the surface area of CeO(2) and decrease its crystallite size. As a result, the active Cu species possess higher dispersion on the support Ce(1-x)Ti(x)O(2) than on pure CeO(2). The strong interaction between the dispersed Cu species and the support Ce(1-x)Ti(x)O(2) makes the catalysts possess much higher oxidation activity and thermal stability. However, when the ratio of Ti/Ce reaches 5:5, opposite effect is found, due to the highest surface concentration of Ti and the lack of surface highly dispersed copper species.