Synthesis and characterization of iron-doped titania nanohoneycomb and nanoporous semiconductors by electrochemical anodizing method as good visible light active photocatalysts

Iron-doped TiO₂ nanostructures (FeTiO₂NSs) were prepared by in situ electrochemical anodizing of titanium in a single-step process in the presence of 3, 9, 15 and 21 mM of potassium ferricyanide. For the first time, K₃Fe(CN)₆ was used as the iron source in doping process. The resulting samples were characterized by FE-SEM, XRD and EDX. SEM images of the resulting samples showed that for a specific morphology, appropriate concentrations of potassium ferricyanide are necessary. Diffuse reflectance spectra showed a shift toward longer wavelengths relative to pure TiO₂ nanotube (TiO₂NT). The dependence of photo-activity on iron doping on TiO₂ was studied for photodegradation of methylene blue (MB). After iron-doping, the removal rate of MB increased under visible light radiation. The results showed that FeTiO₂NSs samples have excellent photocatalytic performance. The sample FeTiO₂NSs2 exhibited better photocatalytic activity than the pure TiO₂NTs and FeTiO₂NSs samples fabricated using other iron concentrations. This work demonstrated a feasible and simple anodizing method to fabricate an effective, reproducible, and inexpensive visible-light-driven photo-catalyst for environmental applications.