Photocatalytic Degradation of 4BS Dye by N,S-Codoped TiO2 Pillared Montmorillonite Photocatalysts under Visible-Light Irradiation

The photocatalytic activities of nitrogen and sulfur codoped TiO2 pillared montmorillonite (N,S-TiO2-PILM) for the degradation of 4BS dye under visible-light irradiation (λ >400nm) were studied. The catalysts were synthesized by impregnating doped titania sol into the interlayer of montmorillonite (MMT) and characterized by the UV−vis diffuse reflectance spectra, transmission electron microscopy, and the FT-IR absorption spectra. The ordered structure of MMT was destroyed to some extent and the size of TiO2 particles is about 2−6 nm. The absorption edge of the doped samples shows a red-shift as compared to that of pure TiO2. The photocatalyic activity of N,S-TiO2-PILM with a mole ratio of Ti:S of 1:4 and obtained at 350 °C for 2 h is higher than that of the other samples and Degussa P25 under visible light irradiation. The chromophore in the molecular structure of 4BS was destroyed completely by the photocatalytic reaction and the naphthalene rings and benzene rings were also decomposed partly.