Large-scale synthesis of multi-walled carbon nanotubes in a continuous inclined mobile-bed rotating reactor by the catalytic chemical vapour deposition process using methane as carbon source

2012 ◽  
Vol 188 ◽  
pp. 113-125 ◽  
Author(s):  
Sigrid Douven ◽  
Sophie L. Pirard ◽  
Fang-Yue Chan ◽  
René Pirard ◽  
Georges Heyen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Source ◽  
Chemical Vapour Deposition ◽  
Large Scale ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Deposition Process ◽  
Mobile Bed ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The use of calcination in exposing the entrapped Fe particles from multi-walled carbon nanotubes grown by chemical vapour deposition

2008 ◽  
Vol 94 (3) ◽  
pp. 585-591 ◽  
Author(s):  
Sreejarani K. Pillai ◽  
Letlhogonolo Matlhoko ◽  
Chris Arendse ◽  
Suprakas Sinha Ray ◽  
Mathew Moodley
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Catalytic synthesis of carbon nanotubes from the decomposition of methane over a Ni–Co/La2O3 catalyst

2009 ◽  
Vol 87 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Long Chen ◽  
Haitao Liu ◽  
Keli Yang ◽  
Jiankang Wang ◽  
Xiaolai Wang
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Single Step ◽  
Methane Decomposition ◽  
Gravimetric Analysis ◽  
Catalyst Composition ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The production of multi-walled carbon nanotubes (MWNTs) by the catalytic chemical vapour deposition (CCVD) method was examined over a series of Ni–Co/La2O3 catalysts with methane as the carbon source. The catalyst composition and the reaction conditions were optimized by analyzing the effluent gas with gas chromatography. Various techniques, such as X-ray diffraction (XRD), Transmission electron microscopy (TEM), Raman spectra, and Thermal gravimetric analysis (TGA) were used to characterize the catalysts and products. The results indicate that the unreduced catalyst 30Ni–10Co/La2O3 showed the highest activity for methane decomposition, and the highest carbon yield, being 624.2%, was obtained over this catalyst at 700 °C after 60 min of reaction with hydrogen as carrier gas. TGA results suggest that the purity of carbon nanotubes (CNTs) can reach up to 98 wt% after a single-step purification by hydrochloric acid.Key words: carbon nanotubes, catalytic chemical vapour deposition, methane decomposition, Ni–Co/La2O3 catalyst.

scholarly journals Synthesis of Multi-Walled Carbon Nanotubes by Chemical Vapour Deposition and Post-Synthesis Treatment by Dielectrophoresis

2021 ◽  
Author(s):  
◽  
Xianming Liu
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Electric Field ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Iron Phthalocyanine ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

<p>Carbon nanotubes (CNTs) are a group of pure carbon solid materials that possess one-dimensional structures with diameters down to less than one nanometre. They have interesting physical properties such as very high tensile strength, metallic and semiconducting conductivity, and great potential for applications. This work investigates the synthesis, alignment and purification of multi-walled carbon nanotubes, which were characterized by Electron Microscopy, measurement of electrical properties and Raman scattering. Synthesis of multi-walled carbon nanotubes (MWNTs) was carried out by Chemical Vapour Deposition, using three different precursors: Fe(NO3)3, ferrocene and iron phthalocyanine. Vertically aligned "forests" of large numbers of MWNTs were achieved using ferrocene and iron phthalocyanine as precursors. Products from iron phthalocyanine yield more graphitic CNT nanostructures, as determined by Scanning Electron Microscopy, Transmission Electron Microscopy, Thermogravity Analysis, Raman microscopy and Energy Dispersive X-ray spectroscopy. Patterned growth of vertical MWNTs arrays with a resolution of 2 microns was also obtained, using a predeposited substrate. A High Resolution Transmission Electron Microscope was employed to investigate the inner structures of individual MWNTs, giving well-resolved images of concentric nanostructures with inter-lattice spacings of 0.34 nm. Techniques for purification and manipulation of CNTs are required before CNTs' excellent properties can be exploited. In this thesis, dielectrophoresis (DEP) under high-frequency AC voltages using an array of micron-scale electrodes was adopted as the technique to align MWNTs between these, electrodes. This technique is effective for MWNTs since their long cylindrical structure and the high mobility of their charge carriers allow them to be electrically polarised. As a result, MWNTs experience large DEP forces in an AC electric field. In our experiments, inter-digitated electrodes were used to apply the electric field to CNT suspensions in various solvents. Alignment of CNTs along their axis was achieved within the gaps between adjacent electrodes at a frequency larger than 1.1 MHz, The AC admittance changes between the electrodes were monitored and were observed to be a clear reflection of the accumulation process of MWNTs. Also it was identified that distilled water was a better solvent than ethanol and isopropanol for DEP purpose on MWNTs. In addition, a prototype device was built to selectively purify MWNTs from as-grown samples by combining DEP and re-circulating fluid flow. It was found that this device is able to decrease the impurity content of MWNTs, which is collected on the electrode array, from the suspension of as-grown samples.</p>

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