Formation Mechanism and Structure of Monatomic Carbon Films in Ethylene Decomposition on the Pt(111) Surface According to XPS Data

The interaction of ethylene with a Pt(111) single-crystal surface was studied using X-ray photoelectron spectroscopy. It was found that both two-dimensional flat graphite islands and curved fullerene-like carbon structures or nanotubes can be formed depending on the reaction temperature of ethylene and the presence of dissolved carbon in the bulk of the crystal. It was assumed that the size and curvature of the islands depend on the size of terraces on the single-crystal surface.     

Fluorination of multiwall nitrogen-doped carbon nanotubes

A film of oriented nitrogen-doped multiwall carbon nanotubes was grown on a silicon substrate as a result of the thermolysis of an acetonitrile + ferrocene mixture. The fluorination of the film by BrF₃ vapor at room temperature removed the substrate; however, the vertical orientation of the nanotubes was not destroyed. Analysis of micrographs of a fluorinated sample obtained with a high-resolution transmission electron micro-scope showed that only the surface walls of the nanotubes were fluorinated. The fluorine concentration of the product as determined from X-ray photoelectron spectroscopy was about 16%. A comparison of the N1s spectra of the starting and fluorinated samples showed that the nitrogen atoms of CN_x nanotubes changed their electronic state as a result of fluorination. Matching of the X-ray photoelectron spectroscopic data with the results of quantum-chemical calculations for fragments of fluorinated nitrogen-doped nanotubes showed that fluorine atoms preferred to attach to pyridine-like nitrogen atoms or to carbon atoms in the ortho or meta positions relative to a nitrogen atom.     

Synthesis,Properties, and Dispersion of Few‐Layer Graphene Fluoride

We have fluorinated few‐layer graphene (FLG) by using a low‐temperature fluorination route with gaseous ClF₃. The treatment process resulted in a new graphene derivative with a finite approximate composition of C₂F. TEM studies showed that the product consisted of thin transparent sheets with no more than 10 fluorographene layers stacked together. Spectroscopic methods revealed a predominantly covalent nature of the C? F bonds in the as‐synthesized product and we found no evidence for the existence of so‐called “semi‐ionic” C? F bonds, as observed in bulk C_xF. In contrast to the case of graphite and typical (thick) expanded graphites, fluorination of FLG did not lead to the intercalation of ClF₃ molecules, owing to the lack of a 3D layered structure. The approximate “critical” number of graphene layers that were necessary to form a phase of intercalated compound was estimated to be more than 12, thus providing a “chemical proof” of the difference between the properties of few‐layered graphenes and bulk graphites. Fluorographene C₂F was successfully delaminated into thinner layers in organic solvents, which is an important property for its integration into electronic devices, nanohybrids, etc.     

X-ray emission and X-ray photoelectron spectroscopic studies of fullerene fluoride C<Subscript>60</Subscript>F<Subscript>24</Subscript>

The structure of the fullerence fluoride C₆₀F₂₄ of the T _h symmetry contains two types of chemically different carbon atoms, namely, atoms of isolated double bonds and atoms of CF groups. X-ray photoelectron and x-ray emission spectroscopic studies of C₆₀F₂₄ revealed a difference in the widths of the x-ray bands corresponding to these types of atoms. Nonempirical quantum-chemical calculations performed for C₅₉NF ₂₄ ⁺ ions with a hole in the C 1s core level of the fullerence fluoride showed that the difference in the bandwidths may be due to the fact that the vibrational states of the system are different when 1s electrons are removed from chemically nonequivalent atoms.