Synthesis and characterization of carbon nanotubes over binary Fe-Co- CaCO3 Catalyst.

Abstract

The influence of synthesis parameters such as mass of support, drying temperature and drying time on the yield of Fe-Co/CaCO3 catalyst prepared by the wet impregnation method using 23 factorial design of experiment was investigated in this study. The suitability of the produced catalyst for the production of carbon nanotubes in a catalytic vapour deposition method was also investigated. Results obtained indicated that highest yield of 95.71 % of the catalyst after calcination was obtained at the synthesis conditions of 10g of catalyst, drying temperature of 120oC and drying time of 12 hours. Particle size analysis of the catalyst revealed that the catalyst sizes are in the ranges of 96.6-10.9 nm, with specific surface area of 3.904m2/g while the HRTEM analysis shows that the catalyst is highly crystalline and well dispersed without agglomeration. Results of the characterization conducted on the carbon nanotubes produced shown that the carbon nanotubes produced is a multiwall carbon nanotube. The TGA analysis revealed that the multiwalled carbon nanotubes produced is thermally stable. While the XRD shows characteristic of graphene layers that make up the tube walls at 2θ values of 25.8736o and 44.6584 o. TEM and SEM/EDS images exhibit a clearly defined multiwall concentric tubular morphology, with 92.29 wt % C with inner diameter of 16 nm. The MWCNTs had aspect ratio of 265 with length of 4.8 μm and specific surface area of 274.06 m2/g and pore volume of 62.97 cm3 g-1. It can be inferred from the various analysis conducted that the developed catalyst is suitable for multiwalled carbon nanotubes in a catalytic vapour deposition reactor.