Electron Stimulated Desorption (ESD) of Ammonia on TiO2(110): The Influence of Substrate Defect Structure
Electron stimulated processes for NH3 adsorbed on rutile TiO2(110) have been studied by means of XPS and mass — resolved ESDIAD (electron stimulated desorption angular ion distribution). We have used three differently prepared TiO2 surfaces to study the influence of the substrate defect structure on the interaction with NH3: a stoichiometric nearly perfect surface, a high — temperature annealed slightly oxygen deficient surface and a sputtered highly oxygen deficient surface. In the limit of a stoichiometric surface, electron irradiation induces the desorption of NH3 molecules. When the highly oxygen deficient TiO2 surface is used as substrate, both desorption and electron stimulated dissociation of NH3 take place with atomic nitrogen the final product of the dissociation process. These measurements provide direct evidence for the role of surface defects of an oxide substrate in electron stimulated reaction pathways.
KeywordsElectron Irradiation Ti02 Substrate Electron Bombardment Saturation Coverage Electron Stimulate Desorption
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