OXYGEN INTERACTION WITH PALLADIUM HYDRIDE AND TITANIUM HYDRIDE SURFACES

Oxygen interaction with thin palladium hydride (PdHx) and titanium hyd ride (TiHy) films obtained in situ under controlled conditions in UHV apparatus has been studied. The surface potential (SP) measurements ha ve been carried out to distinguish between elementary steps of surface processes during hydrides formation, oxygen adsorption on Pd (Ti) and O-2 reaction with PdHx and TiHy. Mass spectrometry has been applied t o determine gas phase composition. It has been found that O, interacti on with PdHx at 195 K leads to H2O formation with the hydride decompos ition. O-2 interaction with TiHy within a temperature range of 78-195 K causes hydrogen replacement on the surface and in the subsurface reg ion by oxygen. Hydrogen is removed to the gas phase.