A simple electrochemical oxidation method to prepare highly ordered Cr-doped titania nanotube arrays with promoted photoelectrochemical property

► Cr-TiO2NTs were prepared via an electrochemical oxidation method. ► Potassium dichromate was used as the source of Cr dopant. ► Cr-TiO2NTs showed high photoelectrocatalytic activity to remove organic pollutant. Highly ordered Cr-doped TiO2 nanotube arrays (Cr-TiO2NTs) were prepared by the electrochemical oxidation of Ti substrate in glycerol/fluoride electrolyte solution containing potassium dichromate. The Cr-TiO2NTs were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicated that Cr3+ was successfully introduced into TiO2 nanotubes and Cr doping inhibited the crystal phase change of TiO2 from anatase to rutile under high annealing temperature. Compared with pure TiO2NTs, the Cr-doped TiO2NTs exhibited higher photocurrent response, which was influenced by the concentration of Cr(VI) dopant and annealing temperature. The efficient removal of methyl orange (MO) indicated the high photoelectrocatalytic (PEC) activity of Cr-TiO2NTs.