Preparation and characterization of Zr doped TiO2 nanotube arrays on the titanium sheet and their enhanced photocatalytic activity

This paper described a new method for the preparation of Zr doped TiO2 nanotube arrays by electrochemical method. TiO2 nanotube arrays were prepared by anodization with titanium anode and platinum cathode. Afterwards, the formed TiO2 nanotube arrays and Pt were used as cathode and anode, respectively, for preparation of Zr/TiO2 nanotube arrays in the electrolyte of 0.1 M Zr(NO3)4 with different voltage and post-calcination process. The nanotube arrays were characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and UV–Vis diffusion reflection spectra (DRS). The photocatalytic activities of these nanotubes were investigated with Rhodamine B as the model pollutant and the results demonstrated that the photocatalytic efficiency of Zr doped TiO2 nanotubes was much better than that of TiO2 nanotubes under UV irradiation. Zr/TiO2 nanotube arrays doped at 7 V and calcined at 600 °C (denoted as TiO2-7 V-600) achieved the best photocatalytic efficiency and the most optimal doping ratio was 0.047 (Zr/Ti). TiO2-7 V-600 could be reused for more than 20 times and maintained good photocatalytic activities.