Abstract

The 0,5Pd/Ce0,6Zr0,4Ox/SiO2; 1,5Pd/Ce0,6Zr0,4Ox/SiO2; 0,5Pd/Ce0,7Tb0,3Ox/SiO2 and 1,5Pd/Ce0,7Tb0,3Ox/SiO2 catalysts were prepared by incipient wetness impregnation technique from aqueous solutions of palladium, cerium, zirconium and terbium chlorides. The catalysts were characterized by X-ray fluorescence (XRF), surface area, X-ray diffraction (XRD), CO chemisorption and Temperature-Programmed reduction (TPR). The catalytic behavior was studied using CO oxidation reaction. The TPR results showed that the addition of Tb or Zr promoted the reducibility of cerium oxide at lower temperatures. CO chemisorptions and TPR results allowed to concluded that Pd addition to Ce0,6Zr0,4Ox/SiO2 and Ce0,7Tb0,3Ox/SiO2 supports generated PdO species of different nature that influence in the catalytic performance. The catalytic activity results showed that Zr addition enhances the catalytic activity of the samples and 0,5Pd/Ce0,6Zr0,4Ox/SiO2 catalyst was the most active (Light off temperature = 140 ºC). The light-off temperatures indicated that low Pd loading favored the reaction.