Inexpensive, upscalable nanotube growth methods

Despite of the very promising foreseen applications, the use of carbon nanotubes in wider range is still limited by the high production costs. In this paper, our latest results concerning two inexpensive methods of carbon nanotube growth with the promise of industrial upscaling are presented. In case of the DC “arc in water” method, the effect of the angle of the two electrodes on the product yield was investigated. The highest nanotube yield and lowest amount of impurities were found at 90° electrode angles. We have studied the applicability of several liquid hydrocarbons and other metallocenes different from the most widely used benzene/ferrocene solution in case of the injection CVD or “spay pyrolysis” method. Toluene, xylene, cyclohexane, cyclohexanone, n-hexane, n-heptane, n-octane and n-pentane were used as carbon source and cobaltocene and nickelocene as catalyst source. All these compounds were found to be suitable for nanotube production. The highest yield and the best quality were obtained when a mixture of ferrocene–nickelocene was used as catalyst and xylene as carbon source.