Synthesis of coaxial nanotubes: Titanium oxide sheathed with silicon oxide

Abstract

The TiO2–SiO22 composite nanotubes with coaxial structure synthesized by sol-gel template method were presented. This process included 2 steps: first, grow SiO22 nanotubes in the pores of anodic alumina with a diameter of 200–250 nm; second, form TiO2 nanotubes within the SiO22 nanotubes. The TiO2 nanotubes with intact SiO22 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.