Methanol adsorption on graphene

TL;DR

This study uses first-principles density functional calculations with vdW-DF to analyze how methanol molecules adsorb on graphene, revealing preferences for cluster adsorption and orientations parallel to the surface.

Contribution

It provides detailed adsorption energies and orientations of methanol on graphene using a dispersion-inclusive DFT method, comparing results with previous computational and experimental data.

Findings

Adsorption favors clusters or high coverage over single molecules.

Methanol C-O axis tends to be parallel to graphene surface.

Calculated adsorption energies agree with previous measurements and methods.

Abstract

The adsorption energies and orientation of methanol on graphene are determined from first-principles density functional calculations. We employ the well-tested vdW-DF method that seamlessly includes dispersion interactions with all of the more close-ranged interactions that result in bonds like the covalent and hydrogen bonds. The adsorption of a single methanol molecule and small methanol clusters on graphene are studied at various coverages. Adsorption in clusters or at high coverages (less than a monolayer) is found to be preferable, with the methanol C-O axis approximately parallel to the plane of graphene. The adsorption energies calculated with vdW-DF are compared with previous DFT-D and MP2-based calculations for single methanol adsorption on flakes of graphene (polycyclic aromatic hydrocarbons). For the high coverage adsorption energies we also find reasonably good agreement with previous desorption measurements.