from the conferences organized by TANGER Ltd.
Graphene is unarguably very promising material for countless applications including also gas sensing. For this particular application, it is very beneficial to understand the nature and strength of interaction of graphene with the adsorbed molecules. Molecular dynamics (MD) simulations matured to a very useful technique providing insights into complex molecular systems on the atomistic scale. However, the prediction potential of classical MD is given by quality of used parameters, including parameters for Lennard-Jones (LJ) term describing dispersion and repulsion part of intermolecular interaction potential. So far, LJ parameters used for graphene have not been thoroughly tested. Using MD we quantified the adsorption enthalpies of several organic volatile molecules (dichloromethane, nitromethane, ethanol, acetone, acetonitrile, ethyl acetate, hexane, cyclohexane, dioxane, benzene, and toluene) to a few layered graphene surface. The calculated adsorption enthalpies were compared with those acquired experimentally using an inverse gas chromatography technique. For each molecule, seven set of simulations were performed with altered LJ parameters and the accuracy of derived adsorption enthalpies was assessed. The average error of Δ⟨HFF⟩ in respect to ΔHexp suggests that OPLS-AA parameters delivered the best agreement with experiments. Needless to say that all tested LJ parameters were suitable for semi-quantitative estimates of the interaction energies of the molecules with the graphene. This implies that MD simulation can provide correct order of adsorption enthalpies of adsorbates and OPLS-AA in addition provides reliable quantitative estimates.
Keywords: Graphene, nanomaterials, molecular dynamics, force field, adsorption enthalpies© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.