Diffusion of hydrogen in Pb β″ alumina

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Abstract
Hydrogen diffuses into Pb β‘ alumina during ion exchange of Na β‘ alumina in molten lead halide salts. The hydrogen resides in the lattice as OH− groups with the protons bound at several kinds of sites. The intrinsic diffusion coefficients of hydrogen and deuterium determined from analysis of infrared absorption profiles following isotope exchange are 9.1, 5.3, and 1.1.×10−7 cm2/s at 515, 455, and 350 °C, respectively. These data fit an Arrhenius equation with an activation energy of 0.54 eV and a preexponential factor of 2.67×10−3 cm2/s. Protons are transported through the conduction layers by hopping to adjacent O= ions. The principal contribution to the activation energy is the energy required to break the O–H bond.