A hybrid molecular dynamics simulation/pore network model approach was developed for predicting diffusion in nanoporous carbons. This approach was computationally fast, and related to the structure of the real material. The pore network model takes into account both the geometrical (a distribution of pore sizes) and topological (the pore network connectivity) characteristics of nanoporous carbons, which were obtained by analysing adsorption data. The effective diffusion coefficient was calculated by taking the transport diffusion coefficients in single slit-shaped model pores from molecular dynamics simulation and then computing the effective value over the pore network model. The reliability of this approach was evaluated by comparing the results of the pore network model analysis with a more rigorous, but much slower, simulation applied to a realistic model material, the virtual porous carbon. Good agreement was obtained between the diffusion coefficients for the pore network model and the virtual porous carbon, indicating the reliability of the hybrid molecular dynamics simulation/pore network model method and it could be used in industry for materials design.

A Pore Network Model for Diffusion in Nanoporous Carbons: Validation by Molecular Dynamics Simulation. Cai, Q., Buts, A., Seaton, N.A., Biggs, M.J.: Chemical Engineering Science, 2008, 63[13], 3319-27