Combined use of the truncated pore network model (TPNM) and the kinetic Monte Carlo method was proposed here to find hydrogen and methane effective self-diffusivities (Deff). It was found that for Knudsen and free molecular diffusion in the simulated materials, the Deff/Vt versus specific surface area curve almost obeyed a power law. The KMC/TPNM approach was also used to predict the self-diffusion coefficients of hydrogen in Vulcan XC-72 and of methane in a carbon aerogel. The obtained values were within the expected range. The KCM/TPNM method was computationally fast and permitted study of diffusion in the network, synchronously and globally, thus avoiding its fractionation in single pores and the use of just one geometrical model to describe the porous spaces.

A Kinetic Monte Carlo Approach to Diffusion in Disordered Nanoporous Carbons. A.Ramírez: Chemical Engineering Science, 2011, 66[22], 5663-71