Controllable preparation of helical carbon nanofibers by CCVD method and their characterization

Helical carbon nanofibers (HCNFs) with the diameter less than 80 nm were produced through catalytic chemical vapor deposition by acetylene pyrolysis with a catalyst derived from the decomposition of copper tartrate at 270 °C. Thermogravimetric and differential scanning calorimetry, x-ray diffraction, atomic force microscopy, scanning electron microscopy and transmission electron microscope were used to characterize the reaction products. The results show that heating rate of copper tartrate has a significant effect on catalyst particle size and fiber morphology. Three different kinds of fiber morphologies can be obtained at the heating rate of 1–10 °C min−1. The formation mechanism of carbon nanofibers indicates that catalyst particles with symmetric shape and small size were suitable for the growth of regular HCNFs.