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.
The Pore Ceramic Membrane Centre, Delft University of Technology, Julianalaan 136, 2618 BL Delft, The Netherlands.
A W C
AW
van den Berg
S T
ST
Bromley
E
E
Flikkema
J
J
Wojdel
Th
T
Maschmeyer
J C
JC
Jansen