A new perspective for effect of S and Cu on the photocatalytic activity of S, Cu-codoped nano-TiO2 under visible light irradiation

Sulfur and copper codoped TiO2 nanoparticles were prepared by sol-hydrothermal process. And the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectra analysis, scanning electron microscopy, Brunauer Emmett Teller analysis, UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectra and X-ray fluorescence analysis. It was found that the S, Cu-codoped TiO2 became amorphous with the increase of Cu content, and copper on the surface of TiO2 existed in the oxidation state of Cu(II) while S in the form of S6+ species. And the codoped particles had higher surface area, smaller particle size, stronger spectral response in visible region compared with pure TiO2. The effects of doping amount in a wide range, catalyst dosage, and recycle on the photocatalytic activity of the codoped catalysts were investigated with Acid Orange 7 as the model compound under visible light illumination (lambda > 447 nm). The results showed that S (2.0 %), Cu (5.0 %) codoped TiO2 had the highest visible light photocatalytic activity and good reusability performance. The kinetic study showed that this photocatalytic process coincided with the Langmuir-Hinshelwood pseudo first order reaction model.