Multi-walled carbon nanotubes (MWCNTs) were synthesized by arc discharge in a magnetic field and a low pressure helium gas using mixtures of FeS/Co, FeS/Ni and FeS/Co/Ni catalysts. The synthesized carbon materials indicated a high-purity of MWCNTs related to decreasing the metal catalysts results from applying the magnetic field which was investigated by X-ray diffraction (XRD) analysis and a high-yield of MWCNTs with less amorphous carbon in the presence of the magnetic field for all mixtures as shown by scanning electron microscopy (SEM). Raman spectroscopy was used to characterize the MWCNTs. The ratio of intensity of the graphitic mode to the defect mode (IG/ID) showed that the quality and crystallity of MWCNTs, which were synthesized using FeS/Ni and FeS/Co/Ni decreased in the presence of magnetic field while the quality of MWCNTs, synthesized using FeS/Co increased. Thermo gravimetric analysis (TG/DTA) was performed for quantitative MWCNTs purity assessment. Results showed that the purity of MWCNTs was increased for all cases in the presence of a magnetic field. This was attributed to the concentration of carbon monomers in the arc plasma with the magnetic field.

Keywords: Multi-Wall Carbon Nanotubes (MWCNTs), Arc Discharge, Magnetic Field, Catalysts.