Preparation of Iron and Chromium Co-Doped TiO2 Nanotubes and Study of Their Photoelectrochemical Properties

Abstract

Fe and Cr-doped, Fe-Cr co-doped, and pure TiO₂ nanotubes have been fabricated by single-step titanium anodization. Morphology, crystal structure, elemental composition, and the photoelectrochemical characteristics of the synthesized photoanodes have been investigated by various methods. The photoelectrochemical activity of TiO₂ nanotubes has been improved by doping, and co-doping under Xe light compared with the undoped TiO₂ nanotube irradiation. The results indicated that the performance of the prepared samples was significantly improved under the same conditions compared with the undoped nanotubes. The best co-doped TiO₂ sample (Fe₄₀Cr₆₀), prepared by the anodization of titanium in dimethyl sulfoxide (DMSO) solvent including 7.2 mM potassium chromate and 4.8 mM potassium ferricyanide as the chromium and iron sources, respectively, demonstrated photocurrent density of over 200 μA/Cm², which is four times superior to that of the pure TiO₂ nanotube. This study presents a novel approach to improve the photoelectrochemical properties of TiO₂ nanotubes through (Fe-Cr) co-doping using a one-step electrochemical anodization method. Furthermore, the synergistic effect between Fe and Cr significantly enhances the photoactivity of the TiO₂ nanotubes, resulting in improved charge separation efficiency and photocurrent density compared to pure TiO₂ nanotubes. The ability to capture visible light and the photoelectrochemical performance of the co-doped nanotubes were shown to improve under illumination by visible light.