Kinetic study of a ceria-promoted Mo2C/γ-Al2O3 catalyst in dry-methane reforming

The kinetics of dry-methane reforming has been studied over a ceria-promoted Mo2C/gamma-Al2O3 (3 wt% Ce, 30 wt% Mo) catalyst at temperatures between 800 and 900 degrees C, and at CH4 and CO2 partial pressures up to 0.31 bar. Oxidation of the Mo2C catalyst, which has plagued earlier kinetic studies, was avoided by co-feeding CO to produce a CO : CO2 ratio of 3. The activation energy obtained from the data fit to a power law rate expression of 45.5 kcal/mol was found to be similar to that of bulk Mo2C. However, the activity of the ceria-promoted catalyst, on a per unit mass of Mo2C, was significantly higher than that of the bulk and is attributed to the higher metal dispersion of the former. A reaction mechanism, involving CH4 activation on Mo2C particles and CO2 activation on both ceria and Mo2C particles, with carbidic carbon extraction by oxygen on ceria as the rate-determining step, is consistent with the derived kinetic model and the high activation energy. (c) 2006 Elsevier Ltd. All rights reserved.