Search

WE have investigated the mechanism of ammonia oxidation on platinum using a molecular beam to sample in collision-free conditions the species from the surface for mass-spectroscopic analysis. With controlled molecular flow of the reactants to the surface, it was possible to achieve a molecular flux at the surface equivalent to immersion in a gas at pressures up to 10−2mm Hg, while ensuring that reaction products had a negligible chance of returning to the surface. The technique was outlined in a previous communication1. Preliminary results reported there supported the earlier conclusion of Fogel et al.2that oxidation proceeded directly to nitric oxide on the catalyst surface.