Synthesis of coaxial nanotubes: Titanium oxide sheathed with silicon oxide

Abstract

The TiO2-SiO2 composite nanotubes with coaxial structure synthesized by sol-gel template method were presented. This process included 2 steps: first, grow SiO2 nanotubes in the pores of anodic alumina with a diameter of 200-250 nm; second, form TiO2 nanotubes within the SiO2 nanotubes. The TiO2 nanotubes with intact SiO2 sheaths were more uniform than those with sheaths partly removed. The existence of Ti-O-Si bonds and the amorphous sheaths is supposed to take an important role in the formation of composite nanotubes.