Synthesis of magnetic carbon nanotubes via Co-pyrolysis of eucalyptus oil with bimetallic Ni-Fe catalyst

Abstract

Magnetic carbon nanotubes (MCNTs) have been specified one of the most promising nanomaterials. They have been applied in many applications due to special electrical, mechanical, and chemical properties. Additionally, magnetic carbon nanotubes could be easily handled by using magnetic field. There are many production developments for increasing in yield and quality of MCNTs. In this thesis, bimetallic Ni-Fe catalyst was investigated for its possibility to improve MCNT synthesis. Nickel content was impregnated on the surface of ferrocene which is the source of Fe content. The catalyst is called ‘ferrocene impregnated with nickel nitrate’. Eucalyptus oil, which mainly contains eucalyptol, was used as carbon precursor for MCNT synthesis. Experimental investigation on influence of catalyst types, synthesis temperature, and molar ratio of eucalyptus oil to catalyst demonstrated was conducted. It was found that MCNT synthesis with the highest total mass yield of 17.1% and the highest crystallinity (ID/IG ratio) of 0.82 could be achieved under the condition of 4:1 ferrocene impregnated with nickel nitrate, synthesis temperature of 800 °C and 5:1 molar ratio of eucalyptus oil to catalyst. Additionally, the CNTs had ferromagnetic properties as VSM results. From experimental, ferrocene impregnated with nickel nitrate could provide higher crystallinity degree of MCNTs than use of ferrocene from 1.19 to 0.82. Thermal stability also increased from oxidation temperature of 515 °C to 559 °C. Moreover, the new catalyst also achieved higher yield than using nickel nitrate from 7.7% to 17.1%. Ni-Fe bimetallic particles in MCNT products were also observed by XRD results.