Evaluation of kinetic models for the partial oxidation of methane to synthesis gas over a Pt/PrCeZrOx catalyst coated on a triangular monolith

The evaluation of kinetic models for the partial oxidation of methane to synthesis gas over a 1.4-wt% Pt/Pr0.3Ce0.35Zr0.35Ox catalyst coated on the surface of a triangular corundum channel is presented. The mathematical form of the tested models accounts for global surface steps. The formulation of reaction steps for two cases proposed in the literature contained lumped formulations to restrict reasonably the number of parameters to estimate. One mechanism considering an oxygen assisted methane activation and another considering methane dissociation without oxygen involvement were tested. In both cases a satisfying description of the experimental data was possible, suggesting that the initial activation of methane is of less importance for the overall progress of the partial oxidation than the oxidation of carbonaceous intermediates to adsorbed carbon monoxide assumed in both cases. Comparing the kinetics over unsupported platinum extensively reported in literature to the data over the 1.4-wt% Pt/Pr0.3Ce0.35Zr0.35Ox catalyst in this work reveals significantly different rates for oxygen adsorption and carbon monoxide oxidation. These differences are explained by considering the active role the ceria plays in the catalyst performance. (C) 2009 Elsevier B.V. All rights reserved.