Published online by Cambridge University Press: 09 August 2013
Density functional theory and statistical calculations are combined to address the chemical stability and structure of epoxy functionalizations of single-layer graphene. Our computations show that at oxidation levels of O:C<0.5, the Gibbs free energy of formation per epoxide amounts to about 0.6 eV, and the structure of the epoxy functionalizations presents local order and long-range disorder. The positive energy value indicates that in air at p=1 bar and room temperature, epoxy functionalizations of graphene are unstable and prone to spontaneous reduction. Our calculations show also that formation and release of O2 is a slow process whose kinetics is controlled by large energy barriers, the formation of very stable intermediate species, and unlikely electronic transitions.