Carbon nanotube formation over supported catalysts

Catalytic synthesis and characterization of multi-wall fullerene nanotubes are presented. Supported transition metal catalysts were prepared by different methods and were tested in the decomposition of hydrocarbons. Reactions were carried out in a fixed bed flow reactor at 700°C at atmo-spheric pressure. Both activity and selectivity of catalyst samples depended mainly on the following parameters: catalyst support, transition metal, initial reactant, and reaction temperature. The quality of the product was charac-terized by TEM. Although the ends of these catalytically produced carbon nanotubes are often closed by fullerenic half-onions, they can be opened with ease in a relatively gentle liquid-phase oxidation procedure. Neither drastic purification process with HF nor oxidative treatment destroyed the quality of the tubes. IR and XPS investigations confirmed that carbon nano-tubes having inner diameter larger than 1–2 nm show graphitic feature.