Effect of Iron Oxide and Silica Doping on Microstructure, Bandgap and Photocatalytic Properties of Titania by Water-in-Oil Microemulsion Technique

The microemulsion method was successfully used to prepare a series of TiO2, Fe oxide and SiO2 doped TiO2 nanoparticles at Ferri atomic ratio of 10% and Si/Ti atomic ratio of 15%. The molar ratio of water to surfactant (W-0) was 2. The samples were calcinated at 350 degrees C. The structural features of TiO2, Fe oxide and SiO2-TiO(2)were investigated by XRD, UV-Visible spectroscopy, SEM and TEM. XRD data verified the formation of typical characteristic anatase form in all the prepared Fe and SiO2-doped TiO2 samples. In comparison with the pure TiO2, Fe oxide and SiO2-TiO2 samples were relatively large in particle size, indicating that doping with Fe oxide and SiO2 can help in increasing the particle size. The role of SiO2 and Fe oxide doping could be related to the reduction in bandgap of the titania particles; this, in turn, could increase the ability of the particles in absorbing photons with energy in the visible spectrum. The doping of highly stabilized SiO2, Fe oxide in the titania matrix lead to the significant red shift of optical response towards visible light owing to the reduced bandgap energy. Among all the pure Fe and SiO2 doped TiO2, Fe oxide-TiO2 sample showed the highest activity of the photocatalytic decomposition of methylene blue (k = 2.1 x 10(-2) min(-1)).