| Abstrakt: |
The kinetic study of the total oxidation of methane over a La0.9Ce0.1CoO3 catalyst has been achieved. A discrimination among the five multistep rate-controlling models, preselected in a preceding study (Stud. Surf. Sci. Cat. 2001, 133, 599−604), was carried out on the basis of experimental data from an integral fixed-bed reactor using a sequential experimental design. According to the selected model, the overall rate is controlled by the rate of three elementary steps, i.e., (a) active surface oxygen formation, (b) the reaction between surface oxygen species and gas-phase methane, and (c) the desorption of reaction products. The kinetic constants of the model were determined using weighted regression. The experimental conversions could be predicted with an average error of lower than 5%. Both reaction products inhibit the reaction, although H2O causes much stronger inhibition. When the partial pressure of water in the feed is significantly higher than the one produced in the reaction, the desorption becomes an equilibrium process and the overall rate is determined only by the two elementary steps a and b. |
