HYDROXYL RADICAL FORMATION DURING METHANE OXIDATION AND WATER DECOMPOSITION ON PT MEASURED BY LASER-INDUCED FLUORESCENCE

Laser-induced fluorescence (LIF) was used to monitor the formation and desorption of OH. radicals over a Pt wire during the catalyzed oxidation of methane. As in the Pt-catalyzed oxidation of hydrogen, the apparent activation energy for OH. desorption, E(a), depends strongly on the fuel-to-oxygen ratio, varying from approximately 33 kcal/mol at high O2/CH4 values to approximately 56 kcal/mol at low O2/CH4 ratios. The reaction of surface oxygen with D2 during the decomposition of H2O on Pt shows that the surface oxygen concentration influences E(a) for OH. desorption on platinum.