The kinetics of hydrogen desorption from and adsorption on zirconium hydride

Three sets of independent experiments were conducted to determine the kinetics of hydrogen desorption from and adsorption Oil delta-zirconium hydrides. One method involved measurement of hydrogen gas pressure-buildup as a result of dehydriding in a closed vessel. The other two involved thermogravimetric experiments, measuring the rate of mass loss during dehydriding under vacuum. Zeroth-order desorption and first order (with respect to gas-phase hydrogen) adsorption kinetics was determined. The Arrhenius dependence of rate constants showed excellent agreement among different experimental data. The activation energies for desorption and adsorption processes were determined as 205 +/- 8 and 86 +/- 15 kJ mol(-1) respectively. (C) 2009 Elsevier B.V. All rights reserved.