Molecular-dynamics analysis of the diffusion of molecular hydrogen in all-silica sodalite.
In order to investigate the technical feasibility of crystalline porous silicates as hydrogen storage materials, the self-diffusion of molecular hydrogen in all-silica sodalite is modeled using large-scale classical molecular-dynamics simulations employing full lattice flexibility. In the temperature range of 700-1200 K, the diffusion coefficient is found to range from 1.610(-10) to 1.810(-9) m(2)/s. The energy barrier for hydrogen diffusion is determined from the simulations allowing the application of transition state theory, which, together with the finding that the pre-exponential factor in the Arrhenius-type equation for the hopping rate is temperature-independent, enables extrapolation of our results to lower temperatures. Estimates based on mass penetration theory calculations indicate a promising hydrogen uptake rate at 573 K.
van den Berg
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AW
The Pore Ceramic Membrane Centre, Delft University of Technology, Julianalaan 136, 2618 BL Delft, The Netherlands.
Bromley
S T
ST
Flikkema
E
E
Wojdel
J
J
Maschmeyer
Th
T
Jansen
J C
JC