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We have studied the formation of coke during the thermal coupling of an equimolecular methanehydrogen mixture at 1230°C and under a one-atmosphere pressure. Coke samples are recovered in rectangular boats placed along the pyrolysis reactor. The deposits show a non-homogeneousness of coke along the reactor in terms of deposition rate and in terms of structure. We observed at least two kinds of coke...
The structural components and the internal organization of carbon cathodic deposits fabricated using an arc with the conditions adjusted for the effective production of nanotubes have been characterized by transmission electron microscopy (TEM), high resolution electron microscopy (HREM) and scanning electron microscopy (SEM). Typically, such deposits are columnar structures oriented along the growth...
A new kind of carbon whisker, different from others, has been found by means of high resolution electron microscopy and field emission scanning electron microscopy. Carbon layers are almost perpendicular to the whisker axis and a spiral structure is formed around it. Structure analysis indicates the growth process consists of two stages; firstly, carbon layers stacked in turbostratic manner, and then...
A review of literature on various kinds of pyrocarbons is given. Their characterization by optical microscopy, TEM imaging (transmission electron microscopy) and diffraction techniques is discussed. Various models are also described critically, as well as the possible mechanisms of deposition.
We report the growth of pillar-like cylindrical structures consisting of densely packed and vertically aligned multiwalled carbon nanotubes by exposing Ni-coated oxidized-Si (001) substrates to a xylene-ferrocene mixture. The nanotube pillars have a diameter between 10 and 100 μm, and lengths of several tens of micrometres. Formation of circular microcracks in the film allows ferrocene and xylene...
Samples of condensable material collected from low-pressure premixed and diffusion benzene/oxygen/argon flames were analyzed chemically to determine fullerene yield and by high-resolution transmission electron microscopy to characterize the fullerenic material on and within the soot particles. Results show that fullerene formation is sensitive to changes in operating conditions, such as fuel/oxygen...
Submicron vapour grown carbon fibres (carbon nanofibres) grown by the floating catalyst method (Sample A), using hydrogen sulphide and ammonia to suppress soot formation, have been subjected to a comprehensive structural analysis, by high resolution transmission electron microscopy, PEEL, X-ray diffraction and gas adsorption. Results were compared to those obtained from an industrial sample (Sample...
The effect of electrolyte temperature on the passivity of solid electrolyte interphase (SEI) was investigated in 1 M LiPF 6 -ethylene carbonate/diethyl carbonate (50:50 vol.%) electrolyte, using galvanostatic charge-discharge experiment, and ac-impedance spectroscopy combined with Fourier transform infra-red spectroscopy, and high resolution transmission electron microscopy (HRTEM). The galvanostatic...
Reaction of propene over silica-, alumina- or titania-supported Ru catalysts in a tubular quartz flow reactor at moderate temperatures (500-700 o C) and atmospheric pressure produced Ru containing carbon nanofibres/tubes. TEM studies revealed that the fibres/tubes grew away from the support and contained Ru metal particles in their tips. The results indicate that sintering of the Ru during...
An optimised isolation procedure of single-wall carbon nanotubes (SWNTs) from a SWNT soot without using any surfactant is reported. Amorphous carbon and small graphitic particles were washed away with N-methyl-2-pyrrolidone (NMP) and acetone. A large amount of graphite-coated metal particles were removed with the oxidation of the SWNT material with HNO 3 (6.5 and 4 M) and by washing the oxidised...
Carbon nanoparticles synthesised by laser pyrolysis of hydrocarbons in a flow reactor have been investigated as a function of laser power. Samples are cross-characterised by high resolution transmission electron microscopy (HRTEM) and infrared (IR) spectroscopy. Nanoparticles appear highly aromatic in character in all the experimental conditions explored here. As the flame temperature in the interaction...
Single-wall carbon nanotubes (SWNTs) have exceptional strength and stiffness and high thermal and electrical conductivity, making them excellent candidates for aerospace structural materials. However, one of the most fundamental challenges is purifying the SWNTs. The purpose of this study was to develop a simple purification process for SWNTs, along with an understanding of the purification process...
Silicon carbide nanotubes with medium surface area (30-60 m 2 /g) were successfully prepared by reaction between carbon nanotubes and SiO vapor according to the shape memory synthesis (SMS). The gross morphology of the carbon nanotubes was maintained during the carburization process. A calcination in air at 600 o C was performed to remove unreacted carbon domains in order to obtain...
Composite flakes of carbon, silicon carbide (SiC) and carbon nanotubes were synthesized by spray pyrolysis employing a slurry of ferrocene (Fe(C 5 H 5 ) 2 ) and SiC powders in xylene at 1000+/-50 o C. These flakes were characterized for their microstructure and composition by transmission electron microscopy, scanning electron microscopy and high-resolution electron...
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