Electrochemical Fabrication of Strontium-Doped TiO2 Nanotube Array Electrodes and Investigation of Their Photoelectrochemical Properties

In recent years, considerable efforts have been made to improve the performance of photoactive nanostructured materials for water-splitting applications. Herein, we report on the fabrication and photoelectrochemical properties of highly ordered Sr-doped TiO2 nanotube arrays synthesized via a one-step electrochemical anodization technique. Nanotube arrays of Sr-doped TiO2 were synthesized via anodization of titanium foil in aqueous electrolytes containing NH4F and various concentrations of Sr(OH)(2) at different electrolyte pHs. The morphology and quality of the fabricated materials were found to be significantly affected by the pH of the electrolyte as well as the solubility limit of Sr(OH)(2) in the test electrolyte. The photoelectrochemical measurements revealed that Sr doping can significantly improve the photoconversion efficiency of the material. Using Sr-doped TiO2 nanotube arrays, an electrode photoconversion efficiency of 0.69% was obtained, which is more than 3 times higher than that of the undoped nanotube arrays (0.2%) fabricated and tested under the same conditions.