Preparation and enhanced photocatalytic activity of S-doped TiO₂/ palygorskite composites

Abstract

Using tetrabutyl titanate and thiourea as titanium and sulphur source, S-doped TiO2/palygorskite (S–TiO2–Pal) composites were prepared by a solgel method. The XRD patterns of S–TiO2–Pal photocatalysts exhibited the characteristic reflection at 2θ values of 8.3° of Pal gradually disappear, while those of the quartz become more intense with the increase in calcination temperature (400–600 °C). The photocatalytic activity of composites was evaluated by photocatalytic degradation of Reactive Black KN-B (KN-B), which is exposed under UV light at the wavelength of 254 nm and visible light of 11 W. The results showed that when the mass ratio of S to TiO2 was 1:3, calcination temperature 500 °C and pH value of dye solution 2.00, the photocatalytic degradation rate of S–TiO2–Pal catalyst under UV and visible lights increased significantly relative to that of TiO2, respectively. Furthermore, the photocatalytic kinetics could be well fitted with the classical first-order Langmuir–Hinshelwood model.