Study of the Variables in the Synthesis of Carbon Nanotubes by the Spray Pyrolysis of Benzene–Ferrocene Mixtures

Abstract

Pure multiwalled carbon nanotubes were synthesized by the spray pyrolysis of benzene–ferrocene mixtures at 1173–1273 K. Several variables were studied: temperature, ferrocene concentration in benzene, pump (feed) rate of benzene–ferrocene mixture, and flow rate of carrier gas (argon). Characterization of the CNTs and the effects of the variables were studied with the help of X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetry. The yield and morphology of CNT was found to be optimum at 1273 K. The effect of temperature on the yield of CNT is explained thermodynamically. Also, the standard Gibbs energy of formation of C6H6(s), which is a new thermodynamic data, is generated. Ferrocene concentration affected the yield inversely. The pump rate controlled the number of walls of the CNT produced and the control of argon flow rate helped to achieve proper alignment of the CNTs.