Preparation, characterization and electronic structures of Fe-doped TiO2 nanostructured fibers

Mesoporous and nanostructured Fe-doped TiO2 fibers were fabricated on a large scale by sol–gel method combined with the polyorganotitanium as the precursor and ferric nitrate as dopant. The prepared fibers were characterized by XRD, XPS, SEM, TEM, N2 adsorption–desorption isotherms and UV–vis spectroscopy. The photocatalytic activity was evaluated by photodegradation of methyl orange (MO) aqueous solution under UV and visible-light irradiation. Compared with different types of photocatalysts, the 0.5%Fe-doped TiO2 fibers exhibit super photocatalytic activity. This is ascribed to the fact that the Fe-doping induces the shift of the absorption edge into the visible-light range with the narrowing of the band gap and reduces the recombination of the photo-generated electrons and holes. Furthermore, first-principle study for their electronic structures was carried out to confirm the effects of different replaced lattice sites on the red shift of the absorption edge and the changes of the band gap of the Fe-doped TiO2 fibers.