Dielectric and photocatalytic properties of sulfur doped TiO_2 nanoparticles prepared by ball milling

摘要

Sulfur (S) doped commercial TiO_2 P-25 has been achieved by changing the amount of thiourea using ball milling technique. The results of XRD clearly reveal biphasial anatase and rutile mixtures for all prepared samples and doping of S does not change the morphology of the TiO_2. The optical absorption edge of S-doped TiO_2 was red shifted with indirect bandgap energy of 2.8 eV. The dielectric studies confirm that the dielectric constant of TiO_2 increases after doping, however it becomes more conductive. Newly designed S-doped TiO_2 photocatalysts exhibited excellent photocatalytic performance for the degradation of methylene blue (MB) under visible light. The overall photocatalytic activity of 0.11 at.% S-doped TiO_2 was significantly 3-times higher than that of commercial TiO_2 P-25 and complete degradation of MB has taken place after 90 min of irradiation under visible light while only 35% dye degraded when the reaction has been carried out in the presence of undoped TiO_2.