Synthesis of SiO₂ Nanotubes and Their Application as Nanoscale Reactors

SiO 2 nanotubes could be synthesized by hydrolysis of tetraethyl orthosilicate (TEOS) on the surface of carbon nanofibers (CNF), followed by removal of CNF. In the synthesis of SiO 2 nanotubes, CNF acted as templates. The wall thickness and the internal diameter of SiO 2 nanotubes were changed by hydrolysis time of TEOS and the diameter of CNF templates, respectively. The catalysts for the hydrolysis of TEOS were functional groups on the surface of CNF. The methane decomposition was carried out over SiO 2 nanotubes containing Ni metal particles, so that carbon nanotubes with uniform diameter (ca. 8 nm) were formed at the inside of SiO 2 nanotubes. This result strongly indicated that SiO 2 nanotubes worked as nanoscale reactors.