Development of an S-doped titania nanotube (TNT) site-selectively loaded with iron(III) oxide and its photocatalytic activities

We investigated an S-doped titania nanotube (TNT) loaded with Fe2O3 nanoparticles in order to improve photocatalytic activity of S-doped TNT under visible light irradiation. S-doped TNT was successfully prepared using the solid-phase method at 350 °C under aerated conditions. S-doped TNT showed photoabsorption in the 400–500 nm visible light region and showed photocatalytic activity for oxidation of acetaldehyde under visible light irradiation. Loading of Fe2O3 on S-doped TNT remarkably improved the photocatalytic activity of S-doped TNT. PA spectra measurement, which was performed in order to elucidate the mechanism of activity improvement, showed that the efficiency of charge separation between photoexcited electrons and holes was improved because the electrons were trapped by Fe2O3. Enhancement of photocatalytic activity was strongly dependent on the site of Fe2O3 nanoparticles loaded on TNT. PA spectra measurement showed that the photoexcited electrons transferred to Fe2O3 from S-doped TNT under UV light irradiation or to S-doped TNT from Fe2O3 under visible light irradiation.