ABSTRACT
A carbon nanotube (CNT) is a promising material for various applications in the field of medical science, energy engineering, electronics, sports and automobiles, and so forth due to their excellent properties. These applications demand large-quantity and high-quality CNTs. The yield and quality of CNTs depend on different parameters such as the type of catalyst, percentage of the catalyst and type of substrate, the synthesis temperature, type of precursor gases and the method of purification, and so forth. The literature survey suggested that the binary catalyst increases CNTs yield. However, very few studies discussed the effect of ternary catalyst for high-yield CNTs synthesis. This chapter highlights the behavior of ternary catalyst (Fe, Co, Ni) at various temperatures in the range of 600–750°C in the presence of argon atmosphere. The material characterization was carried out with the help of X-ray diffraction (XRD) to identify the active catalyst species for the 118CNT synthesis. It is observed that Fe2O3 and Fe3O4 were present at 2θ=24.33° (012), 33.44° (104), 35.88° (110), 41.17° (113), 43.82° (202), 49.86° (024), 54.55° (116), 58.17° (018), 62.94° (214), 64.48° (300), and 72.72° (101). Similarly, Co3O4 was present at 2θ = 31.26° (220), 36.84° (311), 38.54° (222), 44.80° (400), 55.64° (422), 59.64° (511), 65.22° (400), and 75.32° (533). Further, Ni2O3 was present at 2θ = 31.2, 32.3, 43.4, and 63.2°. The X-ray diffraction (XRD) analysis carried out at 600, 650, and 700°C shows a similar pattern, whereas, it was observed that Fe catalyst starts losing its activity as the temperature rises toward 750°C and it is converted to FeO.
