Control of the outer diameter of thin carbon nanotubes synthesized by catalytic decomposition of hydrocarbons.

Multi-wall carbon nanotubes have been produced by the catalytic decomposition of acetylene. Co-Mo, Co-V and Co-Fe mixtures supported either on zeolite or corundum alumina were used as catalysts. When Fe or V is added to Co, the carbon deposit increases. The nanotubes were characterized by both low and high resolution TEM. From histograms representing the outer diameter distributions, it is clear that the outer diameter of the nanotubes can be controlled by choosing the appropriate catalyst.