KINETICS OF THE BIMOLECULAR REACTION NO-2 ON PT(H)

The reaction of NO + H-2 on polycrystalline wires and foils is studied from temperatures between 550 and 1800 K, and partial pressures betwe en 10(-3) and 1 Torr. N2 and N2O are the main products formed during t his reaction. Below about 750 K and above 1500 K, the rates of N2 and N2O formation are about equal. Both rates go through a maximum, then a minimum and rise again with increasing temperature above 1500 K and 1 200 K respectively. Rate data for the formation of N2 and N2O at low, intermediate and high temperature regimes are fitted with Langmuir-Hin shelwood (LH) bimolecular rate expressions within about +/- 30%. Heats of adsorption for NO and H-2, obtained from these rate expressions ar e 25.3 and 12.4 kcal/mol respectively.