Shape-controlled synthesis of ZrO2, Al2O3, and SiO2 nanotubes using carbon nanofibers as templates

A simple shape-controllable synthesis of oxide nanotubes such as ZrO 2, Al2O3, and SiO2, using carbon nanofibers as template was investigated. The templates were placed in a suction filtering unit and a precursor diluted with organic solvent was dropped into carbon nanofiber templates. It was observed that excess precursor solution was removed by filtration. The precursor adsorbed on the templates was hydrolyzed by the water vapor in air while the carbon nanofiber templates were covered with a thin oxide and hydroxide. Most of the formed oxide had nanotubular structure, indicating that hydrolysis of precursors occurred on the surface of the vapor grown carbon fibers (VGCF). The results show that a variety of oxide nanotubes such as thick, thin, and helical nanotubes reflecting the shapes of carbon nanofibers could be synthesized.