Exploring Adsorption of Water and Ions on Carbon Surfaces Using a Polarizable Force Field

Abstract

Graphene, carbon nanotubes, and fullerenes are of great interest due to their unique properties and diverse applications in biology, molecular electronics, and materials science. Therefore, there is demand for methods that can accurately model the interface between carbon surfaces and their environment. In this letter we compare results for complexes of water, potassium ion, and chloride ion with graphene, carbon nanotube, and fullerene surfaces using a standard non-polarizable force field (OPLS-AA), a polarizable force field (OPLS-AAP), DFT, and ab initio theory. For interactions with water, OPLS-AA with the TIP3P or TIP4P water models describes the interactions with benzene (C6H6) and coronene (C24H12) well; however, for acenes larger than circumcoronene (C54H18) and especially for C60, the interaction energies are somewhat too weak and polarization is needed. For ions interacting with carbon surfaces, inclusion of polarization is essential, and OPLS-AAP is found to perform well in comparison to the highest-level quantum mechanical methods. Overall, OPLS-AAP provides an accurate and computationally efficient force field for modeling condensed-phase systems featuring carbon surfaces.

The Band Gap of Graphene Is Efficiently Tuned by Monovalent Ions

“…Carbonaceous materials offering nanoscale pores are important for a variety of promising applications and technologies. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Most known examples include sensing and catalytic devices, 16,17 electrochemical tools, 7,[9][10][11]18 and biomedical setups. [12][13][14] Graphene and its numerous derivatives are currently pursued actively in connection to supercapacitors and lithium-ion batteries.…”

Direct computation of parameters for accurate polarizable force fields

“…26,27 Even for gas phase dimers or oligomers, electronic polarization contributes significantly to the interaction energy, 9,28,29 and such reference data are therefore often used to validate PFFs. 18,21,[30][31][32] For homogeneous systems, PFFs also improve the correspondence between simulated and experimental data. For example, PFF simulations of organic or ionic liquids showed an improved correspondence of thermodynamic and structural properties with experiment, while also reproducing gas-phase dimer properties.…”

Computational chemistry for graphene-based energy applications: progress and challenges

“…Adapted with permission from Ref 8 . terfaces of graphitic nanostructures with water. 77,79,[83][84][85][86] Zhao and Johnson derived a FF that incorporated polarisability via atomic quadrupoles on graphite and water. 83 These authors found that for weakly polar fluids the polarisation contributions were negligible compared with the Lennard-Jones (LJ) interactions.…”

“…In determining the adsorption energies of ions with a graphene surface in vacuo, Schyman and Jorgensen reported that polarisation was essential. 86 …”