Abstract: The Zn²⁺,Fe³⁺ and Cu²⁺ are doped on TiO₂ nanotubes electrode using dipping method in this study.The properties of doped TiO₂ nanotubes electrode are characterized using some advanced analytic methods.It is found from the images of scanning electron microscope (SEM) and patterns of X-ray diffraction (XRD) that the doped TiO₂ nanotubes electrode,whose nanotubes diameter are range from 60 to 100 nm,still remain the original morphology and anatase crystal structure with 101 crystal face.However,the results of UV-Vis diffusion reflectance spectroscopy (DRS) indicate that the initial absorption edges for the three doped TiO₂ nanotubes electrodes shift at different degree.Energy band gaps of Zn²⁺,Fe³⁺ and Cu²⁺ doped TiO₂ nanotubes are 3.37 eV,3.14 eV and 2.86 eV,respectively.This indicates that the absorption edge of the TiO₂ nanotubes doped with Cu²⁺ is red-shift.

Key words: TiO₂ nanotubes electrode, dipping, dopant, energy band gaps