Synthesis of carbon nanotube composites in nanochannels of an anodic aluminum oxide film

A template carbonization technique was applied for synthesizing carbon nanotubes and metal filled nanotubes. An anodic aluminum oxide film that has uniform and straight channels with a diameter at nanometer level was used as a onedimensional template. The pyrolytic carbon deposition on the channel wall was carried out by exposing the anodic oxide film to hydrocarbon gas at high temperature. The carbon was then liberated from the anodic oxide film by dissolving the alumina template. It was found that the resultant carbon is comprised only of uniform hollow-tubes with open ends. The length and the diameter of the carbon nanotubes are controllable by changing the length and the inner diameter of the channels in the anodic oxide film. By applying this template technique, metal filled uniform carbon nanotubes can also be fabricated. Pt, Ag, and Fe-filled carbon nanotubes were synthesized. If one varies metal the loading and metal reduction methods, various shapes of nano metal compounds can be inserted into the hollow of carbon nanotubes. It should be noted that no metal was observed on the outside walls of the tubes. The metal-filled uniform carbon nanotube thus prepared can be regarded as a novel one-dimensional composite, which has a variety of potential applications.