Improving Visible Light-Absorptivity and Photoelectric Conversion Efficiency of a TiO(2) Nanotube Anode Film by Sensitization with Bi(2)O(3) Nanoparticles

This study presents a novel visible light-active TiO(2) nanotube anode film by sensitization with Bi(2)O(3) nanoparticles. The uniform incorporation of Bi(2)O(3) contributes to largely enhancing the solar light absorption and photoelectric conversion efficiency of TiO(2) nanotubes. Due to the energy level difference between Bi(2)O(3) and TiO(2), the built-in electric field is suggested to be formed in the Bi(2)O(3) sensitized TiO(2) hybrid, which effectively separates the photo-generated electron-hole pairs and hence improves the photocatalytic activity. It is also found that the photoelectric conversion efficiency of Bi(2)O(3) sensitized TiO(2) nanotubes is not in direct proportion with the content of the sensitizer, Bi(2)O(3), which should be carefully controlled to realize excellent photoelectrical properties. With a narrower energy band gap relative to TiO(2), the sensitizer Bi(2)O(3) can efficiently harvest the solar energy to generate electrons and holes, while TiO(2) collects and transports the charge carriers. The new-type visible light-sensitive photocatalyst presented in this paper will shed light on sensitizing many other wide-band-gap semiconductors for improving solar photocatalysis, and on understanding the visible light-driven photocatalysis through narrow-band-gap semiconductor coupling.