title: Adsorption of small organic molecules on graphene.
abstract: We present a combined experimental and theoretical quantification of the adsorption enthalpies of seven organic molecules (acetone, acetonitrile, dichloromethane, ethanol, ethyl acetate, hexane, and toluene) on graphene. Adsorption enthalpies were measured by inverse gas chromatography and ranged from -5.9 kcal/mol for dichloromethane to -13.5 kcal/mol for toluene. The strength of interaction between graphene and the organic molecules was estimated by density functional theory (PBE, B97D, M06-2X, and optB88-vdW), wave function theory (MP2, SCS(MI)-MP2, MP2.5, MP2.X, and CCSD(T)), and empirical calculations (OPLS-AA) using two graphene models: coronene and infinite graphene. Symmetry-adapted perturbation theory calculations indicated that the interactions were governed by London dispersive forces (amounting to ∼60% of attractive interactions), even for the polar molecules. The results also showed that the adsorption enthalpies were largely controlled by the interaction energy. Adsorption enthalpies obtained from ab initio molecular dynamics employing non-local optB88-vdW functional were in excellent agreement with the experimental data, indicating that the functional can cover physical phenomena behind adsorption of organic molecules on graphene sufficiently well.
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 771 46 Olomouc, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Lazar
authors.forename: František
authors.initials: F
authors.lastname: Karlický
authors.forename: Petr
authors.initials: P
authors.lastname: Jurečka
authors.forename: Mikuláš
authors.initials: M
authors.lastname: Kocman
authors.forename: Eva
authors.initials: E
authors.lastname: Otyepková
authors.forename: Klára
authors.initials: K
authors.lastname: Šafářová
authors.forename: Michal
authors.initials: M
authors.lastname: Otyepka
mesh_terms: D000327:Adsorption; D002849:Chromatography, Gas; D006108:Graphite / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D008958:Models, Molecular; D009930:Organic Chemicals; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D009930:Organic Chemicals; D006108:Graphite