Molecular dynamics simulations on the effect of temperature and loading in H2 exohedral adsorption on (3,3)(3,3) and (9,9)(9,9) SWCNTs

The adsorption of H2 on single walled carbon nanotubes is investigated as a function of temperature, H2 loading and diameter of the nanotubes. The physisorption phenomenon is simulated by extensive equilibrium molecular dynamics. The applied intermolecular forces are modeled using the modified form of the well-known Lennard-Jones potential based on the tube curvature. The simulation results of exposing different H2 loadings on (3,3)(3,3) and (9,9)(9,9), at 77,30077,300 and 600 K, under moderate pressure of 10 bar, show that the amount of adsorption is strongly influenced by the applied temperature, and that the adsorption energy is higher for nanotubes with smaller diameters. Moreover, analyzing the deformation of the nanotube adsorbents during the simulation time indicates that increasing the operating temperatures not only decreases the amount of adsorption monotonically but also imposes more nanotube distortions.