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 language | English (US) |
|---|---|
| Pages (from-to) | 4226-4238 |
| Number of pages | 13 |
| Journal | Carbon |
| Volume | 49 |
| Issue number | 13 |
| DOIs | |
| State | Published - Nov 1 2011 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Materials Science(all)
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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 journal › Article
TY - JOUR
T1 - Oxygen migration on the graphene surface. 2. Thermochemistry of basal-plane diffusion (hopping)
AU - Radovic, Ljubisa R.
AU - Suarez, Alejandro
AU - Vallejos-Burgos, Fernando
AU - Sofo, Jorge Osvaldo
PY - 2011/11/1
Y1 - 2011/11/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=79961025553&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79961025553&partnerID=8YFLogxK
U2 - 10.1016/j.carbon.2011.05.037
DO - 10.1016/j.carbon.2011.05.037
M3 - Article
AN - SCOPUS:79961025553
VL - 49
SP - 4226
EP - 4238
JO - Carbon
JF - Carbon
SN - 0008-6223
IS - 13
ER -