Dielectric and photocatalytic properties of sulfur doped TiO2 nanoparticles prepared by ball milling

• Designing of visible light responsive photocatalyst utilizing ball milling.
• Sulphur used as dopant in commercial TiO2 P25 at different atomic percentage.
• S doping resulted in an intense increase in absorption in the visible light region.
• Newly design photocatalyst exhibited excellent photocatalytic performance.
• 0.11 at.% S-doped TiO2 shows 3-times higher activity than that of TiO2 P25.

Sulfur (S) doped commercial TiO2 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 TiO2. The optical absorption edge of S-doped TiO2 was red shifted with indirect bandgap energy of 2.8 eV. The dielectric studies confirm that the dielectric constant of TiO2 increases after doping, however it becomes more conductive. Newly designed S-doped TiO2 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 TiO2 was significantly 3-times higher than that of commercial TiO2 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 TiO2.

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