Growth of carbon nanotubes and nitrogen-doped carbon nanotubes on “carbon nanotube seeds”

Carbon and nitrogen-doped carbon (CN_x) nanotubes were synthesized by detonation-assisted chemical vapor deposition with CNTs as seeds and paraffin as the carbon source and melamine as the carbon/nitrogen source. Transmission electron microscopy and electron energy loss spectroscopy were performed to characterize both materials. CN_x nanotubes exhibited a compartmentalized bamboo-like structure and contained a high concentration of nitrogen (17.3 at %), while the new pure CNTs had hollow cores. The role of the original CNTs added to the raw materials could be ascribed to their curvature and open tip edges, which adsorbed Cn/CN species and assembled them into carbon and CN_x nanotubes.