Desorption of n-alkanes from graphene: a van der Waals density functional study

Abstract

A recent study of temperature programmed desorption (TPD) measurements of small n-alkanes (CN H2N+2) from C(0001) deposited on Pt(111) shows a linear relationship of the desorption energy with increasing n-alkane chain length. We here present a van der Waals density functional study of the desorption barrier energy of the ten smallest n-alkanes (N = 1 to 10) from graphene. We find linear scaling with N , including a nonzero intercept with the energy axis, i.e., an offset at the extrapolation to N = 0. This calculated offset is quantitatively similar to the results of the TPD measurements. From further calculations of the polyethylene polymer we offer a suggestion for the origin of the offset.

Methylbenzenes on graphene

“…For each methyl group added an H atom is also removed, thus the net gain of atoms is one C and two H atoms. One of us found in an earlier study [18], by use of vdW-DF1, that in adsorption of the linear n-alkanes on graphene the gain in adsorption energy per additional CH 2 group added to the length of the alkane molecule is 0.075 eV. This fits reasonably well with the increase found here when we use vdW-DF1: E a increases by 0.090 eV per added methyl group.…”

Finite-temperature properties of nonmagnetic transition metals: Comparison of the performance of constraint-based semilocal and nonlocal functionals

“…Importantly, it also captures the more general problem when nonlocal correlation forces compete with other types of forces [9], for example, giving rise to binding across important regions of low electron densities [10,14]. The method was expected to be relevant in first-principles DFT for both pure vdW problems including regular physisorption [49,[78][79][80], porous-materials gas absorption [81][82][83][84][85][86][87][88][89][90], and DNA base-pair interactions [91][92][93][94][95]. It was also quickly realized that truly nonlocal correlations affect materials descriptions much more broadly than what was perhaps originally anticipated [10,14,57,77,[96][97][98][99][100].…”

Accounting for van der Waals interactions between adsorbates and surfaces in density functional theory based calculations: selected examples

“…This is due to the fact that the adsorbate-substrate interaction is dominated by vdW forces and the parallel orientation maximize this type of interaction. The vdW-DF scheme has been applied to the adsorption of small n-alkanes, from methane to n-decane, and also H 2 and polyethylene, on graphene 97 and compared to experimental data. The linear dependence of the desorption energy barrier with respect to the alkane chain length was found in the calculations.…”

“…CO adsorption on MgO(100) 58 and CO and NO adsorption on Nidoped MgO(100), 59 which are also corroborated by the quite encouraging results from recent works concerning the interaction of CO with the (111) surfaces of Rh, Pt, Cu, Ag and Pd 106 or the interaction of benzene, pyridine, thymine and cytosine with Au (111), 107 where the M06-L method and a periodic model approach were used. Another very hot topic where DFT approaches including van der Waals corrections are being used is in the study of the interaction of graphene with adsorbates 70,77,[97][98][99]108 or with a substrate. 109,110 This is mostly due to the fact that graphene presents unique electronic and mechanical properties, with many thought applications, but graphene is also interesting in part since it constitutes an interesting playground for the testing of dispersion-corrected DFT methods.…”