Carbon nanotubes 1 (CNTs) have generated a great deal of interest due to their unique structure and a wide range of potential applications 2,3. Several methods, such as electric arc discharge, laser ablation and thermal chemical vapor deposition (CVD) through decomposition of hydrocarbons have been successfully developed to produce CNTs 3-6. The arc discharge method can produce high-quality nanotubes and on a relatively large scale. However, it has one fatal drawback for industrial scale production in that it is a discontinuous process and consumes relatively large amounts of energy. Furthermore, the soot contains a lot of by-products such as amorphous carbon and carbon nanoparticles 7, The carbon source is graphite, which is very hard to atomize, because the melting and boiling points are unusually high; about 4100 and 4470 K, respectively. Recently, the thermal plasma jet (TPJ) method has been used to synthesize high-quality CNTs at high temperature by introducing a catalyst source 8,9. This is a continuous process, and the carbon source of hydrocarbons or alcohols is atomized by TPJ at a very high temperature, ~10~4K.
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