Jump to main content
Jump to site search

Issue 37, 2020
Previous Article Next Article

Adsorption-induced clustering of CO2 on graphene

Author affiliations

Abstract

Utilization of graphene-based materials for selective carbon dioxide capture has been demonstrated recently as a promising technological approach. In this study we report results from density functional theory calculations and molecular dynamics simulations on the adsorption of CO2, N2, and CH4 gases on a graphene sheet. We calculate adsorption isotherms of ternary and binary mixtures of these gases and reproduce the larger selectivity of CO2 to graphene relative to the other two gases. Furthermore it is shown that the confinement to two-dimensions, associated with adsorbing the CO2 gas molecules on the plane of graphene, increases their propensity to form clusters on the surface. Above a critical surface coverage (or partial pressure) of the gas, these CO2–CO2 interactions augment the effective adsorption energy to graphene, and, in part, contribute to the high selectivity of carbon dioxide with respect to nitrogen and methane. The origin of the attractive interaction between the CO2 molecules adsorbed on the surface is of electric quadrupole–quadrupole nature, in which the positively-charged carbon of one molecule interacts with the negatively-charged oxygen of another molecule. The energy of attraction of forming a CO2 dimer is predicted to be around 5–6 kJ mol−1, much higher than the corresponding values calculated for N2 and CH4. We also evaluated the adsorption energies of these gases to a graphene sheet and found that the attractions obtained using the classical force-fields might be over-exaggerated. Nevertheless, even when the magnitudes of these (classical force-field) graphene–gas interactions are scaled-down sufficiently, the tendency of CO2 molecules to cluster on the surface is still observed.

Graphical abstract: Adsorption-induced clustering of CO2 on graphene

Back to tab navigation

Supplementary files

Article information


Submitted
29 Jun 2020
Accepted
24 Aug 2020
First published
25 Aug 2020

Phys. Chem. Chem. Phys., 2020,22, 21031-21041
Article type
Paper

Adsorption-induced clustering of CO2 on graphene

G. M. Meconi and R. Zangi, Phys. Chem. Chem. Phys., 2020, 22, 21031
DOI: 10.1039/D0CP03482G

Social activity

Search articles by author

Spotlight

Advertisements