First principles calculations of phenol adsorption on pristine and group III (B, Al, Ga) doped graphene layers

Theoretical study of small aromatic molecules adsorbed in pristine and functionalised graphene

Small aromatic molecules are precursors for several biological systems such as DNA, proteins, drugs, and are also present in several pollutants. The understanding of the interaction of these small aromatic molecules with pristine and functionalised graphene (fGr) can generate different applications. We performed ab initio simulations based on the density functional theory to evaluate the interaction between the aromatic compounds, benzene, benzoic acid, aniline and phenol, with pristine and fGr. The results show that the binding energy for all cases is less than 103.24 kJ/mol (1.07 eV) without substantial modification of the electronic properties, indicating that the interaction occurs through a physical adsorption regime. The results are promising because they suggest that pristine graphene and functionalised graphene are suitable for removing these pollutants, or for carrying molecules for biological applications influenced by π-π and H-bonds interaction.

Density functional theory study of π-aromatic interaction of benzene, phenol, catechol, dopamine isolated dimers and adsorbed on graphene surface

We analyze the influence of different groups on the intermolecular energy of aromatic homodimers and on the interaction between a single aromatic molecule and a graphene surface. The analysis is performed for benzene, phenol, catechol, and dopamine. For calculating the energies, we employ density functional theory within the local density approximation (LDA-DFT). Our results show that the lowest intermolecular energies between the aromatic molecules are related to the T-shaped configurations. This lower energy results from the quadrupole interaction. In the case of the interaction between the graphene sheet and the aromatic molecules, the lowest energy configuration is the face to face. The adsorption energy of a molecule on a graphene surface involves π - π interactions that explain the face to face arrangement. These results provide insight into the manner by which substituents can be utilized in crystal engineering, supramolecular chemistry, bioinspired materials, formation of various molecular clusters, parameterization of force fields suitable for classical simulations, and design of novel sensing, drug delivery, and filters based on graphene.

Tuning near-gap electronic structure, interface charge transfer and visible light response of hybrid doped graphene and Ag3PO4 composite: Dopant effects

The enhanced photocatalytic performance of doped graphene (GR)/semiconductor nanocomposites have recently been widely observed, but an understanding of the underlying mechanisms behind it is still out of reach. As a model system to study the dopant effects, we investigate the electronic structures and optical properties of doped GR/Ag₃PO₄ nanocomposites using the first-principles calculations, demonstrating that the band gap, near-gap electronic structure and interface charge transfer of the doped GR/Ag₃PO₄(100) composite can be tuned by the dopants. Interestingly, the doping atom and C atoms bonded to dopant become active sites for photocatalysis because they are positively or negatively charged due to the charge redistribution caused by interaction. The dopants can enhance the visible light absorption and photoinduced electron transfer. We propose that the N atom may be one of the most appropriate dopants for the GR/Ag₃PO₄ photocatalyst. This work can rationalize the available experimental results about N-doped GR-semiconductor composites, and enriches our understanding on the dopant effects in the doped GR-based composites for developing high-performance photocatalysts.