PNNL

Abstract

The 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?¯. Post irradiation temperature programmed desorption shows a temperature dependent release of H2 but not O2. This process likely involves diffusion and recombination of H? atoms initially trapped between the ?-AlOOH planes followed by recombination at edge and surface sites. H2 production upon thermal annealing irradiated material shows no dependence on flux suggesting the precursor species (H?) trapped within the bulk are long lived.