The effect of carbon precursors (methane, benzene and camphor) on the quality of carbon nanotubes synthesised by the chemical vapour decomposition (original) (raw)
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International journal of materials, 2015
In this paper, carbon nanotubes (CNTs) were synthesized via vapor deposition of methane as a carbon source in the presence of Ni/MgO catalyst. The catalyst crystallinity and morphology was examined by XRD and SEM and its superior size distribution and crystallinity was confirmed. The catalytic methane decomposition was conducted in a chemical vapor deposition reactor at 900 °C. Methane, with the flow rate of 600 ml/min, was used as a carbonous gas and hydrogen and nitrogen were used at the flow rate of 500 ml/min. The obtained carbon was characterized by transmission electron microscopy (TEM) and recognized to be multi-walled carbon nanotubes with an average diameter of ~8.6 nm. The Raman spectrum confirmed a high graphitization degree of the obtained CNTs with an I D /I G ratio of 2.05, indicative of high crystallinity with few structural defects. Moreover, the thermal analysis showed the high oxidation stability of the multi-walled carbon nanotubes. It was concluded that Ni/MgO catalyst can be used as an active catalyst in the production of multi-walled carbon nanotubes (MWCNTs) in the vapor phase deposition process.
Methane Decomposition for Carbon Nanotube production Optimization of the Reaction Parameters
In this study, the chemical vapor deposition (CVD) process in a fluidized bed reactor was employed for the decomposition of methane over a Mo/Ce catalyst. The effects of temperature, flow rate, and catalyst loading parameters on the CNT production have been investigated and optimized using response surface methodology (RSM). The formation of the Mo/Ce catalyst was confirmed using Fourier transform infrared (FT-IR) spectroscopy. Field emission scanning electron microscopy (FESEM) was employed to visualize the surface morphology of the obtained catalyst. The XRD patterns suggested a high crystallinity of the prepared catalyst. Small average particle diameter (253 nm) and high surface area (54.4 m2/g) were reported using a particle size analyzer and Brunauer–Emmett–Teller and Barrett–Joyner–Halenda (BET & BJH) analysis, respectively. The SEM micrographs of the nanocarbons deposited via methane decomposition indicated that uniform carbon nanotubes were grown on the surface of the catalyst. The transmission electron microscopy (TEM) images showed that the carbon nanotubes were multi-walled with an average diameter of ∼18 nm. Raman spectrum was used to evaluate the graphitization degree of the obtained CNTs. The thermal analysis of the nanotubes showed the high oxidation stability of the multi-walled carbon nanotubes.
2006
Since the pioneering report of discovery of carbon nanotubes (CNTs) in 1991 by Iijima, scientists and researchers worldwide have carried out in depth investigations in this new family of carbon because of its myriad properties and potential applications. The synthesis of novel nanoscale material is the main target in current material science. This study investigates the effect of different types of cabon source and and catalyst on the type of CNTs formed via catalytic chemical vapour deposition (CCVD) method. Three types of carbon source i.e. acetylene, methane and ethanol were used for the synthesis of CNTs. The catalysts used in the synthesis of CNTs are monometallic, bimetallic and trimetallic derived from Fe, Co and Ni salts using wet impregnation method. The catalysts were characterized by scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDX). The analysis confirmed the presence of Fe, Co and Ni. The as-synthesized CNTs were characterized using SEM/field...
Production of nanotubes by the catalytic decomposition of different carbon-containing compounds
Applied Catalysis A-general, 2000
Carbon nanotubes were prepared in the catalytic decomposition of different carbon containing compounds over supported transition metal catalysts. Besides acetylene, ethylene, propylene, acetone, n-pentane, methanol, toluene, and methane were tested and each resulted in carbon nanotube formation. The quality of as-made nanotubes was investigated by TEM and was found to be at least as good as obtained in acetylene decomposition. Ethylene and propylene showed somewhat lower reactivity in the buckytube formation with respect to acetylene, simultaneously suppressed formation of amorphous carbon on the outer surface was found.