Oxygen migration on the graphene surface. 2. Thermochemistry of basal-plane diffusion (hopping)

Ljubisa R. Radovic, Alejandro Suarez, Fernando Vallejos-Burgos, Jorge Osvaldo Sofo

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Thermodynamic affinities, activation energies and diffusion coefficients for oxygen mobility on the graphene surface are calculated using density functional theory (DFT). We report and discuss the effects of geometry, charge distribution and heteroatom substitution on the migration of epoxy oxygen on the basal plane: both the driving force and the ease of surface hopping are very sensitive to their variations. A significant decrease in the hopping energy barrier is observed when graphene contains free edge sites and oxygen functionalities, as well as upon an increase in electron density; conversely, the barrier increases as a consequence of electron removal, and the propensity for graphene 'unzipping' also increases. There is a correlation between the hopping barrier and the C-O bond strength of the leaving epoxide group. Under the most favorable conditions investigated, oxygen mobility is quite high, of the same order as that of gas-phase O2 in micropores (ca. 10 -9 m2/s). This is consistent with the increasingly acknowledged role of basal-plane oxygen as a protagonist (e.g., reaction intermediate), instead of a spectator, in the wide variety of adsorption and reaction processes involving sp2-hybridized carbon materials.

Original languageEnglish (US)
Pages (from-to)4226-4238
Number of pages13
JournalCarbon
Volume49
Issue number13
DOIs
StatePublished - Nov 1 2011

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Thermochemistry
Graphite
Graphene
Oxygen
Reaction intermediates
Energy barriers
Epoxy Compounds
Charge distribution
Density functional theory
Carrier concentration
Substitution reactions
Carbon
Activation energy
Gases
Thermodynamics
Adsorption
Geometry
Electrons

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)

Cite this

Radovic, Ljubisa R. ; Suarez, Alejandro ; Vallejos-Burgos, Fernando ; Sofo, Jorge Osvaldo. / Oxygen migration on the graphene surface. 2. Thermochemistry of basal-plane diffusion (hopping). In: Carbon. 2011 ; Vol. 49, No. 13. pp. 4226-4238.
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Oxygen migration on the graphene surface. 2. Thermochemistry of basal-plane diffusion (hopping). / Radovic, Ljubisa R.; Suarez, Alejandro; Vallejos-Burgos, Fernando; Sofo, Jorge Osvaldo.

In: Carbon, Vol. 49, No. 13, 01.11.2011, p. 4226-4238.

Research output: Contribution to journalArticle

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