Preparation of ultra-large-scale catalysts for catalytic vapour deposition of carbon nanotubes

One of the most important issues in the controlled synthesis of carbon nanotubes is finding a simple way to synthesize the catalyst nanoparticles with a controlled size. The preparation of iron nanoparticles via an organic route has been presented in the paper. The nanoparticles, of the diameter ranging between 9.5 and 31 nm, supported on magnesia, were used as a catalyst in chemical vapour deposition to produce bulk scale carbon nanotubes. Two carbon feedstocks ( ethanol and cyclohexane) were examined. In the optimization process, the pyrolysis temperature was varied between 650 degrees C and 850 degrees C. In this simple approach, no additional carrier gas was used. Multiwalled carbon nanotubes with a very low diameter distribution ( 19.5 +/- 2.5 nm) were fabricated. Their composition was analysed via X-ray diffraction. The samples were characterized by the resonance Raman spectroscopy and high- resolution transmission electron microscopy.