The effect of ceria content on the performance of Pt/CeO2/Al2O3 catalysts in the partial oxidation of methane

The effect of CeO2 loading (1-20 wt.%) on the properties and catalytic behaviors of CeO2-Al2O3-supported Pt catalysts on the partial oxidation of methane was studied. The catalysts were characterized by S-BET, X-ray diffraction (XRD), temperature-programmed reduction (TPR) and oxygen storage capacity (OSC). XRD and TPR results showed that the pretreatment temperature of the support influences on the amount of CeO2 with fluorite structure. The pretreatment temperature of the support and CeO2 loading influenced the morphology of Pt. OSC analysis showed a significant increase in the oxygen storage capacity per weight of CeO2 for samples with high CeO2 loading (12 and 20 wt.%). TPR analyses showed that the addition of Pt promotes the reduction of Ce02. This effect was more significant for the catalysts with high CeO2 loading (>= 12 wt.%). The dispersion of Pt, measured by the rate of cyclohexane dehydrogenation, increases with increasing of the pretreatment temperature of the support. It was shown that the kind of the support is very important for obtaining of catalysts resistant to carbon formation. The catalysts with high CeO2 loading (>= 12 wt.%) showed the highest catalytic activity and stability in the reaction of partial oxidation of methane due to a higher Pt-CeO2 interface. (c) 2005 Elsevier B.V. All rights reserved.