The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Multi-walled carbon nanotubes (MWCNTs) have been synthesized from novel butadiynyl-ferrocene-containing compounds. The formation of the MWCNTs occurs in the solid phase at ambient pressure in a typical high-temperature furnace. Heat treatment of the various compounds to temperatures up to 1300°C under atmospheric pressure resulted in the decomposition of the ferrocene units and the formation of Fe...
A dc plasma enhanced chemical vapor deposition process is used to obtain vertically aligned carbon nanofibers (CNFs) from palladium catalysts using an ammonia–acetylene process gas mixture. Transmission electron microscopy is used to elucidate the microstructure of the as-grown fibers revealing different growth anomalies such as a new secondary growth phenomenon which we term hybrid tip growth. Also...
Oxidized multi-walled carbon nanotubes (MWCNTs) were dispersed in aqueous and organic solvents by non-covalent modification with a double-hydrophilic block copolymer, poly(ethylene oxide)-b-poly [2-(N,N-dimethylamino)ethyl methacrylate] (PEO-b-PDMA). The PDMA segments were anchored onto the surface of the oxidized MWCNTs through multi-site zwitterionic interactions between the amino and the carboxyl...
High-temperature pyrolysis of two fullerene precursors – 1,2′-binaphthyl and 1,3-oligonaphthyl – has been investigated. An oligomer of naphthalene with the appropriate orientation of fragments, which contains all 60 carbon atoms, 12 of 20 six-membered rings and 71 of 90 carbon–carbon bonds required to form the C 60 fullerene cage was synthesized in a three-step synthesis from naphthalene....
A composite of multi-walled carbon nanotubes (MWCNTs) and polypyrrole (Ppy) has been synthesized by vapor phase polymerization, and characterized by Fourier transformed infrared spectra, Raman spectra, thermal gravimetric analysis, X-ray diffraction study and scanning electron microscopy. Its gas sensitive characteristics towards NH 3 vapor were investigated at room temperature. It was found...
Palladium catalysts supported on carbon nanofibers (CNFs) and XC-72 carbon were developed by chemically reducing palladium chloride with ethylene glycol. The morphologies and crystal structure of the Pd/CNF catalyst and Pd/XC-72 catalyst were investigated by TEM and XRD, respectively. The electrocatalytical activity of the catalysts was examined via cyclic voltammetry testing techniques. The performance...
Transition metal oxides were synthesized inside the pore system of mesoporous carbon CMK-3. By a wet impregnation, drying and calcination procedure iron, copper, nickel, cobalt, manganese and zinc oxides were formed almost exclusively within the mesopores. A reduction into the metal forms with regard to structural array in the case of zinc oxide and a reduction to manganese(II) oxide for manganese(IV)...
Carbon nanobelts, highly branched carbon nanotubes (CNTs) and carbon nanorods (CNRs) were synthesized by the catalytic pyrolysis of acetylene using Fe-catalyst at different temperatures. The 3D double branched K junction and various 2D single branched Y, L, T junctions on CNTs and CNRs were characterized by SEM, TEM, and Raman spectroscopy. The bamboo shaped hollow interior of the K junction indicated...
Manganese dioxide (MnO 2 ) was coated on carbon nanotubes (CNTs) by simple immersion of the CNTs into a KMnO 4 aqueous solution. The synthesis mechanism was investigated by in situ monitoring of the reduction potential and pH of the solution and supplementary UV–VIS analysis of MnO4- ions in the solution. CNTs were found to act as a reducing agent and substrate for the heterogeneous...
An ultrasonic bonding technique has been developed for bonding single wall carbon nanotubes (SWNTs) onto metal microelectrodes. The bonding was formed by pressing SWNTs against the electrodes with a vibrating press at an ultrasonic frequency. With this technology, low-resistance contacts are achieved between both metallic and semiconducting SWNTs and electrodes. After bonding, the effective Schottky...
Using porous anodic aluminum oxide as template and petroleum pitch as precursor, a massive amount of uniform carbon nanofibers was obtained after thermal treatment. The diameter and length were 300nm and 60μm, respectively. The difference between these and the classic herringbone structure is that the angle between the graphenes and the fiber axis increases regularly along the axis instead of being...
Electron emission from the sidewall of a bent individual multiwall carbon nanotube (CNT) is reported. The CNT was synthesized using a catalytic chemical vapor deposition method and the focused-ion beam technique was used to fabricate the CNT-based electron emitter. With controlled ion bombardment, individual carbon nanotubes can be bent into loops with different radii. An external electric field can...
Electrically conductive cement-based materials are important as multifunctional structural materials. Double percolation has been observed for the first time in the electrical conduction in carbon fiber cement-based materials. It involves fiber percolation and cement paste percolation. The fiber percolation threshold increases with increasing sand/cement ratio and ranges from 0.30 to 0.80vol.% fibers...
The vibrational properties of defects in single-wall carbon nanotubes are investigated with an empirical dynamical model based on force constants fitted to graphite [Al-Jishi R, Venkataraman L, Dresselhaus MS, Dresselhaus G. Phonon modes in carbon nanotubules. Chem Phys Lett 1993;209:77–82]. The defected structures are: an isotopic substitution impurity in a chiral tube, a Stone–Wales defect in a...
Experimental techniques for evaluating the interfacial properties between fiber bundles and the matrix of three-dimensionally reinforced carbon/carbon composites were examined. Specially arranged fiber bundle push-out and pull-out tests were conducted up to 2273K in vacuum. In these tests, a fiber bundle in the specimens was extruded or pulled out by external compressive or tensile loads. Post-fracture...
The energetic surface heterogeneity of four different activated carbons was assessed by the parallel probing at the solid/liquid and solid/gas interfaces. At the solid/liquid interface a method of inverse liquid chromatography, frontal analysis by characteristic point was applied using phenylalanine in water solution as a probe molecule. At the solid/gas interface, argon was used as a probe in the...
Hydrogen adsorption measurements have been carried out at different temperatures (298K and 77K) and high pressure on a series of chemically activated carbons with a wide range of porosities and also on other types of carbon materials, such as activated carbon fibers, carbon nanotubes and carbon nanofibers. This paper provides a useful interpretation of hydrogen adsorption data according to the porosity...
Multi-walled carbon nanotubes (MWCNTs) were efficiently synthesized by catalytic combustion of polypropylene (PP) using nickel compounds (such as Ni 2 O 3 , NiO, Ni(OH) 2 and NiCO 3 ·2Ni(OH) 2 ) as catalysts in the presence of organic-modified montmorillonite (OMMT) at 630–830°C. Morphologies of the sample undergoing different combustion times were observed...
Vapor-grown graphitic whiskers in wood charcoal formed during heat treatment above 2000°C are discussed through electron microscope observations. The whiskers were composed of conical stacked hexagonal carbon layers, with a cone apex angle of 136°. This angle probably helps the successive helical growth of the whiskers. To grow these whiskers, pyrolyzed gas from the walls of wood cells could be used...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.