LAUSR

This paper deals with the kinetics of CH4 dissociation on model Pd/Al2O3 catalysts. The adsorption and conversion of CH4 over oxidized catalysts, fresh or aged, were studied with a temporal analysis of products (TAP) reactor. Single CH4 pulse TAP experiments were performed on a stabilized surface. The experiments are discussed in the light of a selected mechanism involving CH4 decomposition into CO2 taking into account an interaction between the metallic active sites and the support. TAP experiments over the oxidized catalysts confirm the involvement of the metal/support interface, with a spill-over effect. Optimized kinetics parameters validate this interaction of OH species adsorbed on Pd sites with alumina, showing a relatively good agreement between experimental and calculated outlet gas composition. Both fresh and aged catalysts follow the chosen mechanism with the same kinetic constants at 400 °C only an alteration of the catalytic surface areas explain the loss of activity.