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Insulating to conductive carbon films were obtained by controlled vacuum annealing of the disordered carbon films deposited on quartz by sputtering of carbon. The change of conductance of the films has been studied on exposure to the vapors of NH 3 and NO 2 , chosen for their opposite donor–acceptor properties. The chemical sensitivity of conductance along with temperature sensitivity...
We present the absolute infrared (5–50μm) hemispherical reflectance of films produced from commercially available carbon nanotubes. Spectra were obtained with the NPL directional-hemispherical reflectance measurement facility. One group of samples consisted of mats of carbon nanotubes sprayed on copper or silicon substrates. Another group consisted of vertically aligned carbon nanotubes grown on silicon...
Graphene–Bi 2 MoO 6 (G–Bi 2 MoO 6 ) hybrid photocatalysts were prepared by a simple one-step process in which the reduction of graphene oxide (GO) and the growth of Bi 2 MoO 6 crystals occurred simultaneously. The material was characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption–desorption isotherms, X-ray photoelectron...
Graphene decorated with manganese dioxide nanoparticles are prepared by electrostatic adsorption. The manganese dioxide is synthesized by a microemulsion route using the cationic surfactant hexadecyltrimethyl ammonium bromide, which dispersed in water is converted to be positively charged. The surface charge of graphene in water is negative, allowing two forms of manganese dioxide-decorated graphene...
The synthesis of monolayer graphene is the key to graphene’s practical applications. Herein we report a facile and scalable technique to grow monolayer graphene on Cu, Ni, Co, and Fe surfaces using an etching-aided chemical vapor deposition (CVD) process. The growth was performed using an additional step of hydrogen etching in atmospheric pressure CVD after stopping the carbon supply. The etching...
The reduction of graphene oxide (GO) by phytochemicals was investigated using aqueous leaf extracts of Colocasia esculenta and Mesua ferrea Linn. and an aqueous peel extract of orange (Citrus sinensis). The prepared GO and phytoextract reduced GO (RGO) were characterized by ultraviolet–visible spectroscopy, Raman spectroscopy and Fourier transform infrared analyses to provide a clear indication of...
The carbon source and growth conditions for single-walled carbon nanotube (SWCNT) growth in hot-wall chemical vapor deposition affect the chirality of the SWCNT ensemble produced. Raman spectroscopy elucidates the trends of the SWCNT semiconducting percentage grown under different conditions. Field-effect transistors using few SWCNTs per transistor were fabricated to allow for a semiconducting SWCNT...
Graphene CVD-grown on Cu has been studied using Raman spectroscopy, X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). Raman data indicate the presence of weak compressive strain at the interface of graphene/Cu. Compared with highly ordered pyrolytic graphite (HOPG), new electronic states in the conduction band are observed for graphene/Cu, which are mainly ascribed to the...
The effects of bucky paper interleaves made from carbon nanofibers on interlaminar shear properties of carbon fiber reinforced composites (CFRPs) are studied. The study includes fabrication of bucky papers, resin impregnation by different techniques, i.e., soaking, hot-compression and vacuum filtration, followed by β-stage curing and the integration with carbon fiber prepregs to produce CFRP composites...
Hydrophobic activated carbons are considered as interesting materials for air or water remediation due to their enhanced affinity for slightly water-soluble organic species. In this context, a commercial activated carbon, in an extruded form, was fluorinated under mild conditions (pure fluorine gas at room temperature) in order to decrease its hydrophilic character and to preserve its microporosity...
This study compares electromagnetic interference (EMI) shielding properties of injection molded versus compression molded multi-walled carbon nanotube/polystyrene (MWCNT/PS) composites, i.e., properties such as EMI shielding effectiveness (EMI SE), electrical conductivity, real permittivity and imaginary permittivity. The injection molded (MWCNT-aligned) samples showed lower EMI shielding properties...
Graphene sheets with different oxygen contents were prepared to functionalize the electrically insulating polymethylmethacrylate (PMMA). The influences of surface chemistry of graphene on rheological, electrical and electromagnetic interference (EMI) shielding properties of its PMMA composites were investigated. The appearance of frequency-independent storage modulus at low frequency suggests a solid-like...
N-doped graphene (NG) was synthesized by annealing reduced graphene oxide (RGO) in an ammonia atmosphere. The dependence of the nitrogen content on the annealing temperature and the type of doping of NG were investigated. The photoluminescence (PL) properties of the RGO and NG samples were studied. The results show that RGO exhibits strong ultraviolet (UV) PL at 367nm. The PL of RGO can be quenched...
Hierarchical porous, magnetic Fe 3 O 4 @carbon nanofibers (Fe 3 O 4 @CNFs) based on polybenzoxazine precursors have been synthesized by a combination of electrospinning and in situ polymerization. The benzoxazine monomers could easily form thermosetting nanofibers by in situ ring-opening polymerization and subsequently be converted into CNFs by carbonization. The resultant...
A spectroscopic study of the amino functionalization of double-walled carbon nanotubes (DWCNT) is performed. Original experimental investigations by near edge X-ray absorption fine structure spectroscopy at the C and O K-edges allow one to follow the efficiency of the chemistry during the different steps of covalent functionalization. Combined with Raman spectroscopy, the characterization gives direct...
Herein we propose a production scheme for conductive films composed of thin graphite sheets with high crystallinity and polymeric resin. The crystalline graphite sheets were successfully produced from natural graphite powder by solution-phase synthesis of graphite intercalation compounds (GICs), following a wet planetary-ball milling under mild conditions. The shear forces in the milling pot lead...
Multiwalled carbon nanotubes (MWCNTs) were treated with a low-pressure water plasma, and the formation of defects on the MWCNT surface was monitored via the changes in the Raman D band to G band intensity ratio that occurred with different plasma treatment times and different temperatures. A kinetic model with two competing processes (defect formation and defect scavenging) was adopted to interpret...
Potassium-doped activated carbon was prepared by mixing potassium salt with polyfurfuryl alcohol precursor followed by carbonization and activation. Several experimental techniques, such as thermogravimetric analysis, gas adsorption, X-ray diffraction and Raman scattering spectroscopy were employed to understand the effects of potassium on the texture and pore structures of the activated carbon, which...
We explore with Molecular Dynamics simulations and a statistical model, the ability of carbon nanotubes to be internalized into a model lipid bilayer as a function of their length. The hydrophobicity is one of the key factors responsible for the insertion process. The membrane asymmetry is also needed to drive a complete translocation. Our data demonstrates that shorter nanotubes have a stronger propensity...
In the present study, we investigated Cs-intercalated single wall carbon nanotubes (SWCNTs) using 133 Cs Nuclear Magnetic resonance. We show that there are two types of Cs cations depending on the insertion level. Indeed, at low concentrations, Static spectra analysis shows that the Cs (α)+ species are fully ionized, i.e. α equal ca.1, while at higher concentrations a second paramagnetically...
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