Abstract: Carbon nanotubes were systhesized at 1100℃ by using ferrocene as the source of catalyst, benzene as source of carbon, hydrogen and argon as the
carrying and diluting gas, respectively, and their structures were analyzed by SEM, TEM and XRD. The inner core of the carbon
nanotube was observed in thinner nanotubes. The formation of carbon nanotubes consists of two steps: the catalysis growth of nanotubes and the deposition
of amorphous carbon. The carbon nanotubes obtained have a hollow diameter of 3～6nm, and are as long as tens of microns. The outer diameter of the
carbon nanotubes is in the range of 20～70nm and uniform along their longitude, and decreases with the increasing of the flow rate of gases. The tips of
the as-grown nanotubes are typically round, though other types of tips existing.

Key words: carbon nanotube, floating catalysis, ferrocene