AVS 46th International Symposium
    Surface Science Division Monday Sessions
       Session SS2-MoM

Paper SS2-MoM1
The Influence of a Catalytic Surface on the Gas Phase Ignition and Combustion of H2+O2

Monday, October 25, 1999, 8:20 am, Room 607

Session: Catalysis on Metals
Presenter: M. Försth, Chalmers University of Technology, Sweden
Authors: M. Försth, Chalmers University of Technology, Sweden
F. Gudmundson, Chalmers University of Technology, Sweden
J. Persson, Chalmers University of Technology, Sweden
A. Rosén, Chalmers University of Technology, Sweden
Correspondent: Click to Email
The OH concentration outside a Pt catalyst at 1300K, in a stagnation flow of 90% O@sub 2@ and 10% H@sub 2@, has been studied by Planar Laser Induced Fluorescence, PLIF, and compared to measurements outside a heated glass surface. The total pressure in the system was varied from 0.2 to 120 torr. At low pressure, surface reactions were observed for the Pt surface, but not for the glass. At higher pressure, gas-phase ignition occurred for both systems, but not at the same pressure: ignition occurred at a lower pressure outside the inert glass surface. Computer modeling using CHEMKIN confirmed these results. The difference in gas-phase ignition is also seen in the modelling results, and it is due to the removal of atomic O and H from the gas by adsorption and reaction on the catalytic surface. The catalytic reaction mechanism on the surface plays an important role as it enhances the removal of radicals, compared to a surface where only radical recombination back to reactants is allowed.