(N,F)-co-doped TiO2-δ beads loaded onto C nanofibers: Excellent visible-light photocatalyst for the degradation of organic dyes and reduction of Cr(VI)

Abstract

TiO2 is an excellent photocatalyst for pollutant disposal due to its high activity, high stability, non-toxicity, low cost and mild reaction conditions. However, its wide band gap (about 3.2 eV), easy recombination of photogenerated electrons and holes owing to the low electrical conduction, as well as easy agglomeration caused by size effect weaken the photocatalytic performance of TiO2. Herein a novel nanocomposite of (N,F)–co-doped TiO2-δ beads loaded onto C nanofibers was prepared via a three-step process of the electrospinning of PAN fibers, deposition of TiO2 via solvothermal synthesis, and the following thermal treatment. The as-prepared nanocomposite exhibits excellent photocatalytic activity for the degradation of pollutants, which can remove 62.5% of RhB, 67.1% of MB and 51% of Cr(VI) under visible light irradiation from a 5 W LED lamp within 60 min, approximately 27.2, 5.2 and 4.6 times those over the commercially available TiO2 powders, respectively, due to the reduced band gap caused by oxygen deficiency together with the elemental doping of N and F, as well as the greatly improved electrical conduction through the C supporter and oxygen defects.