One-pot synthesis and photocatalytic activity of Fe-doped TiO₂ films with anatase–rutile nanojunction prepared by plasma electrolytic oxidation

A novel one-pot low temperature preparation of Fe-doped anatase–rutile TiO₂ (Fe-TiO₂) films is demonstrated using plasma electrolytic oxidation (PEO). Pale yellow TiO₂ films are obtained by PEO treatment of Ti metals in the electrolyte dispersing TiO₂ and Fe₂O₃ particles. The oxidized layer on Ti metal have a sponge-like structure with thickness and pore size of 10 and 0.1–1 μm, respectively. Investigation by X-ray diffraction, X-ray photoelectron spectroscopy, and UV–Vis absorption spectroscopy all indicate that dissolved Fe³⁺ ions in the strong acidic electrolyte are doped into the TiO₂ structure during PEO. The photocatalytic activity of Fe-TiO₂ samples was investigated by studying the photocatalytic decomposition of acetaldehyde. Fe-TiO₂ samples doped with optimum Fe content show visible light photocatalytic activity and further increased photocatalytic activity under UV illumination compared with that of pure TiO₂ films.