Kinetic study of methane oxidation on Pt/BN catalyst

The unique kinetics of hexagonal boron nitride (h-BN) supported Pt catalyst were studied via the catalytic oxidation of methane. The catalyst of 0.37 wt% Pt/h-BN catalyst was prepared using the incipient wetness method. The oxygen concentrations ranged from 10 to 80%. The light-off temperature (at 50% conversion) was approximately 475degreesC under methane concentrations of 4000-10000 ppmv. The intrinsic kinetic data were carefully obtained by eliminating both external and internal resistances of mass as well as heat transfers. The apparent activation energy was estimated to be similar to76 kJ/mol, indicating surface reaction control. The elementary steps and reaction mechanism were established based on the Langmuir-Hinshewood model. The methane deep oxidation over Pt/h-BN was found to be first order with respect to methane and one-fourth order with respect to oxygen. The results suggested that the rate-determining step was the second hydrogen stripping of adsorbed methane on Pt active sites.