Synthesis,Characterization and Photocatalytic Activity of TiO_2 Film/Bi_2O_3 Microgrid Heterojunction

TiO₂ film modified by Bi₂O₃ microgrid array was successfully fabricated by using a microsphere lithography method. The structure and morphology of TiO₂ film, Bi₂O₃ film and TiO₂ film/Bi₂O₃ microgrid heterojunction were characterized through X-ray diffraction, atomic force microscopy and scanning electron microscopy. The optical transmittance spectra and the photocatalytic degradation capacity of these samples to rhodamine B were determined via ultraviolet-visible spectroscopy. The results indicated that the coupled system showed higher photocatalytic activity than pure TiO₂ and Bi₂O₃ films under xenon lamp irradiation. The enhancement of the photocatalytic activity was ascribed to the special structure, which could improve the separation of photo-generated electrons and holes, enlarge the surface area and extend the response range of TiO₂ film from ultraviolet to visible region.