Effects of Ni Loadings on the Structure and Morphology of Carbon Nanotubes Using Nickel Doped Iron Oxide Catalysts

Iron oxide and their different doped iron oxide catalyst have been used for decades and are considered as efficient catalysts in several synthesis schemes including synthesis of carbon nanotubes. The iron oxide of the catalyst is abundant in nature, high catalytic activity at low over potentials, stability in basic media and low cost, making it environmentally and economically attractive. Nickel doped iron oxide catalyst have not been reported in the literature. Doping of nickel over iron oxide catalyst, different percentage 1 %, 5 %, 10 % and 20 % were done by impregnation method. The samples were characterized by X-Ray powder Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) and Thermo Gravimetric Analysis (TGA). Nickel doped iron oxide was used as catalyst for the synthesis of carbon nanotubes (CNTs) and doping changed the morphology of carbon nanotube (CNTs). FTIR results confirmed the doping and presence of different functional groups. Chemical vapor deposition (CVD) was carried out for the synthesis of multiwall carbon nanotubes (MWCNTs) on nickel doped iron oxide catalyst for different percentage (1 %, 5 %, 10 % and 20 %) separately. CVD assembly was carried in tube furnace and the reaction was checked at two different temperature i.e 700 °C and 750 °C and using methane and compressed natural gas (CNG) as precursors. The catalyst was activated in the furnace at 800 °C for an hour. Methane and argon were used in proportion 2 : 1 inside the furnace. SEM showed formation of CNTs at 750 °C with CNG precursor. Formation of CNTs increased with increasing doping with this CNTs was confirmed by SEM.