Radiolytic hydrogen generation from aluminum oxyhydroxide solids: theory and experiment

Exploratory work on gamma exposure to dried solids with chemically-bound water that are typical of those produced on aluminum-clad nuclear fuel in reactor and post-discharge storage has shown a profound production of hydrogen (as the sole gaseous species) from dry boehmite (gamma-AlOOH or Al2O3 center dot H2O) powders and barely observable hydrogen from dry gibbsite (gamma-Al(OH)(3) or Al2O3 center dot 3H(2)O) under gamma irradiation from cobalt-60. A computational investigation of hydrogen bond energies was performed to provide insights to explain the experimental observations. A gas phase or single-molecule model, and a solid phase model were used. For all model reactions, computations indicate hydrogen loss is more favorable for boehmite than for gibbsite, in qualitative agreement with the experimental findings.