Synthesis of a composite consisting of carbon nanotubes and graphite shell-encapsulated cobalt nanoparticles using plasma-enhanced chemical vapor deposition

摘要

We report a simple and effective one-step synthesis route for synthesizing a composite consisted of carbon nanotubes (CNTs) and graphite shell-encapsulated cobalt nanoparticles using plasma-enhanced chemical vapor deposition on Si (100) substrate covered with catalyst Co particles, discharging a mixture of H_2 and CH_4 gas, and characterize the obtained composite by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscope, and X-ray photoelectron spectroscopy. The results show that CNTs align perpendicularly to the substrate and graphite shell-encapsulated Co nanoparticles clung to the external surfaces of aligned CNTs. The diameter of the graphite shell-encapsulated Co nanoparticles increases with increasing the H_2 content in H_2 and CH_4 carbonaceous gas. A possible growth mechanism of the CNTs and graphite shell-encapsulated cobalt nanoparticles composite has been explored.