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 degrees C at atmospheric 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 characterized 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 nanotubes having inner diameter larger than 1-2 nm show graphitic feature.