Efficient visible-light-induced photocatalytic degradation of MO on the Cr–nanocrystalline titania–S

In order to improve visible light photocatalytic activities of the nanometer TiO2, a novel and efficient Cr,S-codoped TiO2 (Cr–TiO2–S) photocatalyst was prepared by precipitation-doping method. The crystalline structure, morphology, particle size, and chemical structure of Cr–TiO2–S were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) techniques, respectively. Results indicate that the doping of Cr and S, cause absorption edge shifts to the visible light region (λ > 420 nm) compare to the pure TiO2, reduces average size of the TiO2 crystallites, enhances desired lattice distortion of Ti, promotes separation of photo-induced electron and hole pair, and thus improves pollutant decomposition under visible light irradiation. The photocatalytic activities of Cr–TiO2–S nanoparticles were evaluated using the photodegradation of methyl orange (MO) as probe reaction under the irradiation of UV and visible light and it was observed that the Cr–TiO2–S photocatalyst shows higher visible photocatalytic activity than the pure TiO2. The optimal Cr–TiO2–S concentration to obtain the highest photocatalytic activity was 5 mol% for both of Cr and S.