Preparation and characteristics of carbon nanotubes filled with cobalt

Carbon nonotubes filled with long continuous cobalt nanorods or nanoparticl es were synthesized by a simple catalytic process. Co(CO)(3)NO was used as the precursor and served as both the source for the carbon nanotubes and fo r the cobalt, the catalyst. Some nanotubes filled with nanorods have big he ads. The Go-filled nanotubes can be separated easily from the products by u sing a permanent magnet. The average diameter of the multiwalled nanotubes is about 40 nm. The cobalt nanorods are a few micrometers long with a diame ter of 20 nm. In addition, some long, ribbonlike structures of flattened na notubes were also observed in the product mixture. After sonication of the product mixture, a small number of nanotube rings with cobalt nanoparticles were found. X-ray diffraction analysis shows the cobalt nanorods encapsula ted in the carbon nanotubes as having an fee and not the stable hexagonal s tructure. A growth mechanism for these filled nanotubes is proposed. XPS an d Raman spectrum were also employed to analyze the products. The de magneti c measurements were conducted to test for its magnetic properties.