Towards a better modelisation of carbon-based nanomaterials

Abstract

The strong indications of the untapped potential of Carbon-based nanostructured materials as next-generation sorbents come mainly from simulation and theoretical work [1]. Dispersive interactions among the various carbon nanostructures (graphene, nanotubes, etc) as well as with guest molecules (H2, CO2, etc) are at the core of the relevant physical mechanisms involved. However, the vast majority of the “in-silico” studies rely on effective pairwise descriptions of the dispersive forces (Lennard-Jones). Recent developments of new van-der-Waals DFT functionals [2] provide a convenient starting point to attain a more accurate representation. By making recourse of the SCARF-RAL cluster we have calculated the energy barriers involved in a specific type of stacking fault in graphite using a dispersive DFT functional. The calculations agree well with the experimental data but, the comparison with the standard pairwise potential calculations reveals a discrepancy of an order of magnitude. We show here our ongoing study of the limits as well as of possible improvements of classical pairwise modelisations of the interlayer interactions.