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Double-wall carbon nanotubes (DWCNTs) have been better prepared by thermally decomposing ferrocene mixed with sulphur in the mixture flows of argon and acetylene at 950-1150 o C. The product of DWCNTs has been systematically studied as a function of the reaction temperature, the partial pressure of hydrocarbon, the sublimed temperature of ferrocene, and the relative molar value of ferrocene...
Chemical vapour infiltration is simulated by deposition of pyrolytic carbon on planar boron nitride substrates and carbon fibers in a hot-wall tubular reactor at about 1100 o C for varied pressure and flow-velocity of methane. The degree of orientation of the deposited graphite-like domains can be monitored via orientation and temperature dependence of the electron spin resonance parameters...
Carbon nanotubes were synthesized from acetylene and hydrogen gas mixture directly on stainless steel plates by sequential combination of rf PECVD and thermal CVD. PECVD was used for nucleation and initial growth of carbon nanotubes while thermal CVD was utilized for further growth of them. In this way decoupling of nucleation and growth of carbon nanotubes was realized, and growth of carbon nanotubes...
The ellipsometric measurements of diamond films, which were deposited onto polished [100]-oriented silicon and rough alumina ceramic substrates by hot filament chemical vapor deposition (HFCVD) technique, have been performed over the spectral range from 3 to 12 μm. The parameters of the films, namely, film thickness and volume fraction for each constituent have been calculated from the ellipsometric...
Amorphous carbon nitride (α-C:N) thin films were synthesized on silicon as electron emitters by the electron cyclotron resonance chemical vapor deposition (ECR-CVD) system in which a negative dc bias was applied to the graphite substrate holder and a mixture of C 2 H 2 and N 2 was used as precursors. The addition of Ar combined with the application of a negative dc bias can...
Amorphous carbon films, characterized by XRD, AFM, SEM and Raman, were deposited from SiCl 3 CCl 3 on quartz substrates at 773-1273 K by low pressure chemical vapor deposition using a hot-wall reactor. XPS studies showed that the films grown at 773 K contained 90% C and 10% Cl, while the films grown at 1273 K contained 100% C. SiCl 4 , CCl 4 and Cl 2 C CCl...
As previously reported, high surface area microporous carbons with long-range order can be synthesized by using zeolite Y as a template. In this work, an attempt is made to synthesize porous carbon using several other types of zeolites (zeolite β, ZSM-5, mordenite and zeolite L). Special attention is paid to whether the structural regularity of each zeolite can be transferred to the carbon structure...
Carbon deposition from ethene, ethine and propene as a function of pressure was studied at various temperatures and two different surface area/volume ratios. Deposition rates as a function of pressure of all hydrocarbons indicate Langmuir-Hinshelwood kinetics which suggests that the deposition process is controlled by the heterogeneous surface reactions (growth mechanism). These kinetics are favored...
Catalytic filamentous carbon (CFC) synthesized by the decomposition of methane over iron subgroup metal catalysts (Ni, Co, Fe or their alloys) is a new family of mesoporous carbon materials possessing the unique structural and textural properties. Microstructural properties of CFC (arrangement of the graphite planes in filaments) are shown to depend on the nature of catalyst for methane decomposition...
Carbon-coated cobalt nanocapsules were synthesized by the chemical vapor-condensation process with cobalt carbonyl (Co 2 (CO) 8 ) used as precursor and carbon monoxide (CO) as carrier gas. The characterization and magnetic properties of carbon-coated cobalt nanocapsules were investigated systematically. The transmission electron microscope (TEM) images showed that the as-prepared nanoparticles...
In-situ optical emission spectroscopy was used to systematically study the influence of nitrogen on the growth of carbon nanotubes (CNTs) by microwave-plasma enhanced chemical vapor deposition at different CH 4 concentrations in a CH 4 /N 2 gas mixture. The results show that CN and C 2 co-exist in the plasma and emission intensities of the two species are correlated...
Trisubsituted derivatives of s-triazine (1,3,5-triazine) with N(i-Pr) 2 , N(i-Bu) 2 , NH(t-Bu), pyridyl, and NHNHMe ligands were used as single-source precursors to produce carbon nitride (CN x ) thin films via hot wall CVD. The precursors are either commercially available or were synthesized in straightforward, one-pot procedures, and the synthesis and characterization of...
We demonstrate that Fe impurities in double-walled carbon nantoubes (DWNTs) may be greatly depressed by improving the experimental setup in a floating catalyst CVD method. In the paper, the effect of different experimental parameters on sample purity has been systematically studied. The possible reasons for the decrease of impurity in the DWNT samples prepared with the improved apparatus are discussed...
Carbon nanotubes (CNTs) were prepared by ethylene decomposition on an Fe/Al 2 O 3 catalyst in a fluidized bed reactor. Their gross defects at different growth periods are evaluated by using a combination of SEM, TGA and Raman spectroscopy. The initially grown CNTs have a much lower thermal stability and more defects as compared to the fully-grown ones. The difference in the defects...
Usually carbon nanotubes (CNTs) containing only one hollow core are obtained from the catalytic decomposition of hydrocarbons when hydrocarbon gases flow straight into the reaction tube. However, unusual carbon nanotubes with multiple hollow cores were observed when the gas-feed method was changed in an attempt to increase CNT production yield using a floating catalyst method. The fraction of multicored...
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