Catalysis Today, Vol.77, No.3, 245-256, 2002
Partial oxidation of methane on Pt/Ce-ZrO2 catalysts
The mechanism of partial oxidation of methane was studied on Pt/Al2O3, Pt/ZrO2 and Pt/Ce-ZrO2 catalysts. The reducibility and oxygen transfer capacity were evaluated by temperature programmed reduction (TPR) and oxygen storage capacity (OSC). The effect of the support on the cleaning mechanism of the catalyst surface was investigated by the sequence of CH4/O-2 pulses. Moreover, temperature programmed surface reaction (TPSR) measurements were performed to evaluate the reaction mechanism. Pt/Ce-ZrO2 catalysts proved to be more active, stable and selective than Pt/Al2O3 and Pt/ZrO2 catalysts. The results were explained by the higher reducibility and oxygen storage/release capacity of Pt/Ce-ZrO2 catalysts, which allowed a continuous removal of carbonaceous deposits from the active sites, favoring the stability and activity of the catalysts, as revealed by the CH4/O-2 pulses. TPSR experiments showed that the partial oxidation of methane proceeded through a two-step mechanism.