Abstract
Anodic aluminum oxide (AAO) film was used as a template to fabricate TiO 2 nanotubes. TiO 2 was deposited into the AAO pores by atomic layer deposition (ALD) at 100 °C. After the top layer of TiO 2 and the AAO template were removed, an ordered array of TiO 2 nanotubes remained on the substrate. The tube thickness increased with the cycle number of ALD. The UV-vis absorption spectra of the samples exhibited a red shift as the thickness increased or after annealing. The photocatalytic activity increased with the increase in the wall thickness of TiO 2 nanotubes. With deposition of Ag nanoparticles on the tubes, the nanoparticles could act as an electron trapper to slow the electron-hole recombination rate, and thus enhance the efficiency of photodecomposition of methyl orange. © 2011 American Chemical Society.