Adsorption of Carbon Tetrahalides on Coronene and Graphene

Abstract

Since carbon tetrahalides CX 4 (X = Cl/Br) are adsorbed on carbon nanotubes and graphene sheets, we have studied the structures, adsorption energies, and electronic properties of CX 4 adsorbed on benzene, coronene, and graphene using dispersion corrected density functional theory (DFT) with hybrid functionals. As compared with the benzene−CX 4 complexes (with binding energy of ∼14/15 kJ/mol) where electrostatic energy is significant due to the halogen bonding effect, the graphene−CX 4 complexes show about three times the benzene−CX 4 binding energy (∼40/45 kJ/mol) where the dispersion interaction is overwhelming with insignificant electrostatic energy. Since the X atoms in CX 4 are slightly positively charged and the X atom's ends are particularly more positively charged due to the σ-hole effect, CX 4 behaves as an electron acceptor. This results in electron transfer from locally negatively charged C sites of benzene/coronene to CX 4 . In contrast, no electron transfer occurs from graphene to CX 4 because of the large work function of graphene and significant electron affinity of CX 4 and because homogeneously charge-neutral graphene has no locally charged sites. Nevertheless, due to the symmetry breaking upon adsorption, the CX 4adsorbed graphene shows a small band gap opening without p-doping. On the other hand, CF 4 behaves as an electron donor due to the negatively charged F atoms, which results in electron transfer from CF 4 to the locally negatively charged C sites of benzene/coronene. Again, no electron transfer occurs from CF 4 to graphene because of high ionization energy of CF 4 , and so the CF 4 -adsorbed graphene opens only a small band gap without n-doping.

Adsorption of Actinide (U–Pu) Complexes on the Silicene and Germanene Surface: A Theoretical Study

“…Two types of models can be used to represent extended systems: cluster models and periodic models. In the cluster model, the 2D surface has been represented by a finite piece (a flake) of the material just like its analogue graphene, which has been represented by six peri-fused benzene rings known as coronene. , In the periodic model, periodic boundary conditions (PBC) will come into play for modeling an infinite system . The latter is the most common method for studying the adsorption of species onto 2D materials.…”

Interfacial Water at Graphene Oxide Surface: Ordered or Disordered?

“…SAPT2+ calculations, proposed as the “silver standard” by Parker et al, were performed on nonperiodic clusters (with the graphene surface represented as coronene , ). These clusters were taken from snapshots from the BLYP-D2 simulation data with θ DW /θ HH values corresponding to peaks in the joint cos­(θ DW )–cos­(θ HH ) distribution for both the BLYP-D2 and OPLS-AA data.…”

“…Energy decomposition analysis has been used extensively in the literature to describe noncovalent interactions 101−103 such as EDA method, 104,105 ALMO-EDA, 106−109 or perturbation methods such as SAPT 81,110 and other wave function methods. 111 SAPT2+ calculations, proposed as the "silver standard" by Parker et al, 110 were performed on nonperiodic clusters (with the graphene surface represented as coronene 112,113 ). These clusters were taken from snapshots from the BLYP-D2 simulation data with θ DW /θ HH values corresponding to peaks in the joint cos(θ DW )−cos(θ HH ) distribution for both the BLYP-D2 and OPLS-AA data.…”

Highly Porous Reduced Graphene Oxide-Coated Carbonized Cotton Fibers as Supercapacitor Electrodes

“…The choice of the M06-2X functional is based upon the inclusion of dispersion corrections, in line with recent works. 38 , 39 The results are presented in Figure 3 , where a d -glucose molecule—representing a cellulose segment integrating a CF—interacts with graphene (I) and GO (II) molecular models. In both cases, we employed a 15 Å × 9 Å sheet.…”