Fabrication of TiO2 nanotube film by well-aligned ZnO nanorod array film and sol–gel process

High density TiO2 nanotube film with hexagonal shape and narrow size distribution was fabricated by templating ZnO nanorod array film and sol–gel process. Well-aligned ZnO nanorod array films obtained by aqueous solution method were used as template to synthesize ZnO/TiO2 core–shell structure through sol–gel process. Subsequently, TiO2 nanotube array films survived by removing the ZnO nanorod cores using wet-chemical etching. Polycrystalline anatase TiO2 nanotube films were ∼ 1.5 μm long and ∼ 100 nm in inter diameter with a wall thickness of ∼ 10 nm.