Electron-Stimulated Formation and Release of Molecular Hydrogen and Oxygen from Boehmite Nanoplatelet Films

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he production and release of H2 and O2 during and after electron (100–1000 eV) irradiation of boehmite nanoplatelet films was studied. H2 and O2 produced during irradiation likely correspond to electron-induced dissociation of the hydroxyls primarily in the terminal surface layers of the boehmite followed by the H· + H· → H2(g) and O + O → O2(g) combinative desorption reactions as well as the abstraction reactions H· + >OH– → H2(g) + >O·̅. Postirradiation temperature-programmed desorption shows a temperature-dependent release of H2 but no additional release of O2. This process likely involves diffusion and recombination of H· atoms initially trapped between the γ-AlOOH planes followed by recombination at edge and surface sites. H2 production upon thermal-annealing-irradiated material shows no dependence on incident electron flux, suggesting the precursor species (H·) trapped within the bulk are long-lived.