| The rate of deposition of carbon nanotubes, their purity and wall thickness was investigated employing different Chemical Vapor Deposition (CVD) processes. Two catalysts, consisting of Al2O3 and Fe2O3 of variable composition, were used, while the carbon precursor was an alcohol (ethanol or methanol). The experiments were carried out in a thermogravimetric CVD reactor which enables continuous monitoring of the evolution of the mass of carbon with time. The final product was analyzed using Scanning Electron Microscopy and Raman Spectroscopy. It was found that product purity and wall thickness was depended on process temperature, the carbon precursor, the concentration of Fe2O3 in the catalyst and the use of hydrogen for catalyst reduction, before or during deposition. |
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