Bulk production of bamboo-shaped multi-walled carbon nanotubes via catalytic decomposition of methane over tri-metallic Ni–Co–Fe catalyst

Abstract

In this work, bamboo-shaped, multi-walled carbon nanotubes were synthesized via methane decomposition over a Ni–Co–Fe tri-metallic catalyst at 1000 °C. The nitrogen absorption (BET), X-ray diffraction (XRD), and particle size analysis results of the catalyst were used to demonstrate the surface area, size distribution, and crystallinity of the sample. The scanning electron microscopy (SEM) micrographs of the nanocarbons deposited via methane decomposition indicated that highly uniform carbon nanotubes were grown on the surface of the tri-metallic catalyst. The transmission electron microscopy (TEM) images showed that the carbon nanotubes were multi-walled and bamboo-shaped with a diameter of ~20 nm. Raman spectra revealed the graphitization degree of the CNTs with an I D /I G of 1.84, indicative of the crystallinity of CNTs with structural defects. The thermal analysis shows the high oxidation stability of the multi-walled carbon nanotubes.