Effects of Catalyst on Carbon Nanotubes Synthesized by Thermal Chemical Vapor Deposition Method

The effects of cobalt, nickel and iron catalyst on carbon nanotubes (CNTs) were examined with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractrometer (XRD) and Fourier transform Raman spectrometer (FT-Raman). The samples were prepared by the thermal chemical vapor deposition (CVD) method at 780 °C under pressure of acetylene gas (C2H2) at 0.5 bar. The average diameter of CNTs grown on Co, Fe and Ni catalyst obtained from SEM image is 100, 90, 70 nm, respectively. The crystallinity and the yield of CNTs synthesized from Ni catalyst were higher than that from Fe or Co catalyst. The Raman peak of radial breathing mode (RBM) region and the TEM images highlighted the hollow tubes of the CNTs. The results indicated that the diameter, the yield and the crystallinity for synthesis of carbon nanotubes were manipulated by the selection of the catalyst.