Adsorption of Organic Molecules to van der Waals Materials: Comparison of Fluorographene and Fluorographite with Graphene and Graphite

0475189 - ÚOCHB 2018 RIV US eng J - Článek v odborném periodiku
Karlický, F. - Otyepková, E. - Lo, Rabindranath - Pitoňák, M. - Jurečka, P. - Pykal, M. - Hobza, Pavel - Otyepka, M.
Adsorption of Organic Molecules to van der Waals Materials: Comparison of Fluorographene and Fluorographite with Graphene and Graphite.
Journal of Chemical Theory and Computation. Roč. 13, č. 3 (2017), s. 1328-1340. ISSN 1549-9618. E-ISSN 1549-9626
Grant CEP: GA ČR(CZ) GBP208/12/G016
Institucionální podpora: RVO:61388963
Klíčová slova: density functional theory * augmented wave method * basis set convergence
Obor OECD: Physical chemistry
Impakt faktor: 5.399, rok: 2017
http://pubs.acs.org/doi/full/10.1021/acs.jctc.6b01130

Understanding strength and nature of noncovalent binding to surfaces imposes significant challenge both for computations and experiments. We explored the adsorption of five small nonpolar organic molecules (acetone, acetonitrile, dichloromethane, ethanol, ethyl acetate) to fluorographene and fluorographite using inverse gas chromatography and theoretical calculations, providing new insights into the strength and nature of adsorption of small organic molecules on these surfaces. The measured adsorption enthalpies on fluorographite range from -7 to -13 kcal/mol and are by 1-2 kcal/mol lower than those measured on graphene/graphite, which indicates higher affinity of organic adsorbates to fluorographene than to graphene. The dispersion-corrected functionals performed well, and the nonlocal vdW DFT functionals (particularly optB86bvdW) achieved the best agreement with the experimental data. Computations show that the adsorption enthalpies are controlled by the interaction energy, which is dominated by London dispersion forces (similar to 70%). The calculations also show that bonding to structural features, like edges and steps, as well as defects does not significantly increase the adsorption enthalpies, which explains a low sensitivity of measured adsorption enthalpies to coverage. The adopted Langmuir model for fitting experimental data enabled determination of adsorption entropies. The adsorption on the fluorographene/ fluorographite surface resulted in an entropy loss equal to approximately 40% of the gas phase entropy.
Trvalý link: http://hdl.handle.net/11104/0272045