Abstract: The Fe₂O₃/TiO₂ nanotubes electrode was prepared using cathodically electrochemical deposition and anodic oxidation method. The properties of the composite electrode were characterized by scanning electron microscopy, transmission electronic microscope, X-ray diffraction, and UV-Vis diffuse reflectance spectroscopy. The decolorization of methyl orange was investigated using the composite electrode as a photoanode. The results indicated that Fe₂O₃ nanoparticles were uniformly dispersed on the surface of TiO₂ nanotubes electrode. The adsorption edge of the composite electrode exhibited a red shift compared with the pure TiO₂ nanotubes electrode. In addition, Fe₂O₃/TiO₂ nanotubes electrode showed higher current density than TiO₂ nanotubes electrode under irradiation. It indicated that the metal oxide modification successfully broadened the absorption spectrum of TiO₂ nanotubes to the visible light region. Moreover, it was in favor of the separation of photo-induced electron-hole pairs. The Fe₂O₃/TiO₂ nanotubes electrode performed higher photoelectrocatalytic activity for the degradation of methyl orange. Furthermore, it was found that methyl orange had a higher decolorization rate under the acidic condition. When the initial pH value was 3, the decolorization rate of methyl orange solution could reach 91.7% under the light irradiation for 5 min.

Key words: ferric oxide, titania, nanotube, photoelectrocatalysis, visible light, methyl orange, degradation