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Carbon aerogels were prepared by polymerization of a resorcinol–formaldehyde mixture using different polymerization catalysts such as: sodium or potassium carbonates, oxalic acid or para-toluenesulfonic acid. The carbon aerogel obtained with this last acid was further CO 2 -activated to 8.5% and 22% burn-off. All samples were characterized by N 2 and CO 2 adsorption at −196...
Single-walled carbon nanotubes (SWNTs) functionalized by ferrocene-grafted poly(p-phenyleneethynylene)s can gelate common organic solvents such as chloroform to form a freestanding carbon nanotube organogel that cannot be redispersed in any organic solvents, indicating the robustness of 3D nanotube network. The drying of SWNT gel on silicon wafer in the air gives a highly convoluted film that is composed...
The carbon nanostructures formed during chemical vapour deposition (CVD) of ethene and hydrogen over an iron(III) oxide catalyst precursor have been investigated. Graphitic nanofibres and carbon nanotubes were both observed during synthesis, with the structures observed depending on the temperature and gas mix (C 2 H 4 and H 2 ) used. Mixtures ranging from 100% to 5% ethene...
Nitrogen molecules have been encapsulated into the central hollows of vertically aligned carbon nitride (CN) multiwalled nanofibers by dc plasma-enhanced chemical vapor deposition with C 2 H 2 , NH 3 , and N 2 gases on a Ni/TiN/Si(100) substrate at 650°C. X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectra showed the existence of nitrogen...
Single-walled carbon nanotubes (SWNTs) are successfully grown on magnesite crystal by pyrolysis of methane gas under moderate conditions, demonstrating the possibility of naturally occurring SWNTs.The obtained SWNTs were analyzed by Raman scattering, transmission electron microscope (TEM), and thermogravimetric (TG) measurements. These measurements revealed that high purity SWNTs having diameters...
The first in situ electron paramagnetic resonance (EPR) spectroelectrochemical study of C 60 fullerene peapods (C 60 @SWCNT) as well as that of single-walled carbon nanotubes (SWCNTs) in different electrolyte solutions describes the formation of spin states by charge transfer reactions. Electrochemical reduction of peapods at high negative potentials causes the production of spins...
High purity multi-walled carbon nanotubes were synthesized from aromatic hydrocarbons (benzene, toluene, xylene and trimethyl benzene) using ferrocene as the source of Fe catalyst. Screening studies of aromatic feeds at 675°C, residence time of 14s and Fe/C atom ratio of 1.07%, resulted in feedstock carbon conversion of 20–31%, CNT yield of 19.8–30.5%, and catalyst yield of 5.3–8.3 (gCNT/gcatalyst)...
The development of the microporosity, pore size distribution and pore network connectivity has been studied in the production of activated carbons from lignite char. Grand Canonical Monte Carlo simulation of adsorption was applied to the characterisation of a set of activated carbons produced at a sequence of times. The pore size distributions obtained from nitrogen at 77K and ethane at 264K were...
Platelet graphite nanofibers are materials produced from the decomposition of carbon monoxide and hydrogen over iron powders. The surface consists of terminated graphite edges, differing from traditional graphite materials in which basal plane graphite surfaces dominate. The 3-dimensional morphology and crystal face exposure on the nanofiber surface was determined by selected area electron diffraction...
The third-order optical nonlinearity in carbon nanotubes (CNT) exposed to an intensive external electromagnetic field has been investigated. The analysis is based on the quantum kinetic equations for the density matrix of π-electrons in CNT. In the regime of weak driving field, the kinetic equations have been solved by the perturbation method and the third-order nonlinear polarizability of different...
Strong vertically aligned Fe-filled multiwalled nanotubes have been synthesised by decomposition of ferrocene in a liquid source CVD process. By varying the reaction parameter such as deposition time, reaction temperature and precursor concentration we determined the influences on the length, diameter and filling yield of the carbon nanotubes. The length and the diameter of the nanotubes are only...
The electronic structure of the (9,0)–(18,0) double-walled zigzag carbon nanotubes in the presence of a uniform transverse electric field is studied by the tight-binding model. The electric field could induce the semiconductor–metal transition, change the direct gap into the indirect gap, alter the subband curvatures, destroy the double degeneracy, produce the new band-edge states, make more subbands...
A variety of nanoporous carbide-derived carbon materials possessing improved pore size distributions were synthesised from a mixture of titanium carbide and titanium dioxide. It was observed that TiO 2 caused partial oxidation of the carbon particles created during high-temperature chlorination of the TiC/TiO 2 mixture. The resulting carbon powder is characterised by narrow pore size...
The kinetics of carbon nanotube (CNT) synthesis by decomposition of CH 4 over Mo/Co/MgO and Co/MgO catalysts was studied to clarify the role of catalyst component. In the absence of the Mo component, Co/MgO catalysts are active in the synthesis of thick CNT (outer diameter of 7–27nm) at lower reaction temperatures, 823–923K, but no CNTs of thin outer diameter are produced. Co/MgO catalysts...
Data on temperature-dependent electrical resistance of buckypaper flakes are presented in this paper. The buckypapers are composed of ropes of aligned single-walled carbon nanotubes doped with HNO 3 , which are treated as mixed systems with their properties being dependent on the treatment performed. The measurements cover rather wide temperature range from 300 up to 900K. In case of untreated...
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