Visible light photocatalytic activity of tungsten and fluorine codoped TiO2 nanoparticle for an efficient dye degradation

Tungsten and fluorine codoped TiO2 (W, F-TiO2) nanoparticles were synthesis by sol-gel method. The XRD analysis shows that all the samples existed as anatase phase of TiO2. Also, the crystalline size of codoped TiO2 is decreasing than the pure and monodoped TiO2. TEM images indicate that grain size of pure and codoped TiO2 nanoparticles are in the range of 15-22 and 6-14nm, respectively. Band gap of codoped TiO2 nanoparticles showed narrowing (2.85eV) when compared to monodoped TiO2 (3.02 and 2.97eV) and pure (3.16eV) nanoparticles. The observed lower intensity from PL study in the codoped TiO2 sample than that in other TiO2 samples indicated that the recombination of photoinduced electrons and holes in TiO2 could be effectively inhibited in the W and F ions. The codoped TiO2 exhibited the highest photocatalytic activity under visible light compared with other TiO2. The codoped TiO2, great visible light absorption is produced by the formation of impurity energy states near both the band edges which also act as both the photogenerated charges to diminish the recombination process.