Formation of carbon nanotubes without iron inclusion and their alignment through ferrocene and ferrocene-ethylene pyrolysis.

ABSTRACT

So far carbon nanotubes grown from the method most common method at present, that is, pyrolysis of ferrocene, invariably contains Fe inclusion. In addition, they are generally grown in random configurations. In the present investigations CNTs without Fe inclusion and in aligned configurations have been prepared by the pyrolysis of ferrocene (C10H10Fe) as well as pyrolysis of ferrocene in the presence of ethylene (C2H4). This has been achieved through optimization of growth parameters, for example, heating rate of ferrocene, pyrolysis temperature, and flow rates of carrier gas argon (Ar) and ethylene (C2H4). The as-synthesized samples have been characterized by transmission and scanning electron microscopic techniques. The optimum results relating to synthesis of carbon nanotubes without Fe inclusion and in aligned configurations have been obtained at 1000 degrees C pyrolysis temperature under flow rates of Ar of approximately 1000 sccm and of C2H4 of approximately 100 sccm. These carbon nanotubes have been found to have an outer diameter between approximately 20 and 60 nm and lengths between approximately 15 and 20 microns.