Partial oxidation of methane on Pt catalysts: Effect of the presence of ceria–zirconia mixed oxide and of metal content Original Research Article

The objective of this work was to study the effects of different noble metal loadings on Pt/CeZrO2/Al2O3 catalysts for the partial oxidation of methane. For both Al and CeZrAl series of samples, the decrease of platinum loading resulted in a significant increase of metallic dispersion. Temperature-programmed reduction and oxygen storage capacity analyses revealed that the sample containing 1.5% Pt presented superior redox properties when compared to the other samples. The catalytic tests showed that the use of smaller Pt contents lead to deactivation. X-ray absorption near edge structure experiments showed that all Pt is in the reduced form above 600 °C. In addition, there is evidence that the partial oxidation of methane proceeds through a two-step mechanism. The best performance was obtained for the 1.5Pt/CeZr/Al catalyst that has the largest platinum content, the presence of a homogeneous solid solution, good metal dispersion and high BET surface area.