The Morphology Of Carbon Nanofibers Prepared By Different Catalysts And The Research On The Growth Mechanism

In this paper, we synthesized the helical and straight carbon nanofibers by the chemical vapor deposition of acetylene with different catalysts such as alloy nanoparticles , metal nanoparticles ,CuO and copper tartrate at the low temperature of 300°C. The morphologies and structures of the carbon nanofibers were studied by SEM,TEM, XRD, IR and TG-DSC etc. The growth mechanism of the carbon fibers was discussed.Helical nanofibers with absolutely symmetric structures were synthesized by the chemical vapor deposition of acetylene with Cu-Ni alloy nanoparticles, Cu-Fe alloy nanoparticles, copper nanoparticles and copper tartrate as catalysts. This is a new type of growth mode. There are always only two helical twin-nanofibers symmetrically grown over a single crystal particle. The two helical nanofibers have absolutely opposite helical senses (If one fiber is left-handed, the other must be right-handed.), but have identical cycle number, coil diameter, coil length, coil pitch and fiber diameter. The two helical carbon nanofibers usually change helical senses (helical reversals) at the coil position of the same cycle number, which may be brought by the change of the crystal face of the catalyst particles during the reaction.The form and dimension of the catalyst particles have a great influence on the morphology of the carbon fibers. The catalyst particles, which locate at the node of the two fibers can be rhombic, triangular, quadrangular, oblong, circular. But the catalyst particles located at the node of the helical fibers almost have regular shape, and whose particle diameter is smaller than that of the straight carbon nanofibers. The small dimension and shape regularity of the faceted catalyst particles included in the fibers accounts for the different morphologies of the resulting products.