Investigation of Fe/MgO Catalyst Support Precursors for the Chemical Vapour Deposition Growth of Carbon Nanotubes

Carbon nanotubes have been grown by the catalytic chemical vapour deposition (CCVD) method using an Fe catalyst supported on MgO. The influence of using either pure MgO or Mg(NO₃)₂ · 6H₂O as the source of the MgO catalyst support as well as the effects of varying the Fe metal loading on the support has been investigated. The catalyst was prepared at room temperature by the wet impregnation method from a mixture of Fe₂(SO₄)₃ · xH₂O and either MgO or Mg(NO₃)₂ · 6H₂O in aqueous solution; the weight percent of Fe/MgO was varied between 5, 10, and 15. Preparation of CNTs was carried out in a horizontal furnace at 900 °C under methane gas with flow rate of 6 litres/min. The supported catalysts and carbon nanotubes (CNTs) were investigated by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction pattern (XRD) and Fourier Transform (FT)-Raman spectroscopy. Results revealed that the number of nanotubes was maximised by using MgO as a support precursor instead of Mg(NO₃)₂ · 6H₂O and also by increasing the amount of Fe.