The electrical and chemical properties of graphene (C(24)H(12)), graphane (C(24)H(24)) and graphene oxide (C(54)H(17)+O+(OH)(3)+COOH) were studied through the density functional theory (DFT) at level of Local Density Approximation (LDA) using a model C(n)H(m) like. The optimized geometry, energy gap and chemical reactivity for the proposed carbon 2D models are reported. It was found that while the graphene and graphane structures have semiconductor behavior, the graphene oxide behaves as semi-metal. However, a transition from semi-mental to semiconductor is predicted if the carboxyl group (COOH) is removed from such structure. The chemically active sites are analyzed on the basis of the electrophilic Fukui functions for each structure.

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In this paper first principles total energy calculations to study the adsorption of amine group (NH2) on graphene (G) and boron nitride (hBN) nanosheets are developed; the density functional theory, within the local density approximation and Perdew-Wang functional was employed. The sheets were modeled with a sufficiently proved CnHm-like cluster with armchair edge. The optimized geometry was obtained following the minimum energy criterion, searching on four positions for each nanosheet: perpendicular to the carbon atom, on the hexagon, inside the hexagon and on the bridge C-C, for the G-amine interaction; and, perpendicular to the B, perpendicular to the N, on the hexagon, and inside the hexagon, for the hBN-amine interaction. A physisorption, with amine parallel to the C-C-C bond with a distance graphene-amine of 2.56 Å, was found. For the case of BN a B-N bond, with bond length equal to 1.56 Å, was found; the amine lies perpendicular to the nanosheet. When the graphene is doped with B and Al atoms a chemisorption with B-N (1.57 Å) and Al-N (1.78 Å) bonds is observed; the bond angle in the amine group is also incremented, 5.5° and 8.1°, respectively. In the presence of point defects (monovacancies) of B in the hBN-amine and C in the G-amine, there exists chemisorption, increasing the reactivity of the sheets.

We have performed first principles total energy calculations to investigate the structural and reactivity parameters of novel N12X12H12 (X=B, Al, Ga, In, Tl) nitrides, in their coronene‐like (C24H12) structure to simulate these sheets. The exchange and correlations potential energies are treated in the Generalized Gradient Approximation (GGA), and the Local Density Approximation (LDA) within the parameterization of Perdew‐Wang and Perdew‐Burke‐Ernzerhof (PWC, PBE) and the double Numeric plus polarization (DNP) atomic base. The chemical potential, hardness and electrophilicity index, as well as bond length are reported. The bond length of the structures is similar to the bulk. The gap between the HOMO and LUMO decreases from BN (5.18 eV) to TlN (1.76 eV). At the same time, the polarity increases except for TlN. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Density functional theory based methods were used for the analysis of the interaction between BC3 (a graphene nanosheet doped with boron), pristine and with point defects (vacancies of carbon – VC and boron – VB), and the H2O molecule.

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