Metal-catalyst-free Growth and Characterization of Nitrogen-doped Carbon Nanotubes

Nitrogen-doped carbon (CNx) nanotbues were synthesized by detonation-assisted chemical vapor deposition with carbon nanotubes (CNTs) as catalysts and melamine as carbon/nitrogen sources. CNTs exhibit high catalytic activity for the metal-catalyst-free synthesis of CNx nanotubes. TEM, EDS, Mapping, XPS, Raman and TG were performed to characterize the synthesized CNx nanotubes. CNx nanotubes exhibit compartmentalized bamboo-like structure, and contain high concentration of nitrogen (ca. 17at%), which is homogeneously distributed within compartment layers and tube walls. The pyridine-like and graphitic N are incorporated into the graphitic network. The nitrogen doping induces the decrease of the graphitization degree and results in lower oxidation-resistance temperature. The synthesis of CNx nanotubes without metal catalysts will facilitate the applications of CNx nanotubes.