Preparation of SnS2/TiO2 by a thermo-solvent ultrasonic method and its high photo-catalytic performance for decontamination under visible light

Numerous attempts have been made to develop visible-light-driven SnS2 photo-catalysts for decontamination; however, the practical application of such materials has always been limited by the rapid recombination of electrons and holes under sunlight irradiation. In this study, SnS2/TiO2 with petal-like SnS2 nanosheets grown on TiO2 spheres was successfully prepared by a simple one-step low-temperature thermo-solvent ultrasonic method. This SnS2/TiO2 could effectively utilize photon energy in sunlight and simultaneously maintain a high electron transfer rate. The SnS2/TiO2 composites showed the highest photo-catalytic activity and good stability towards decontamination (taking methyl orange as the model contaminant) compared with S2- and Sn4+ doped anatase TiO2 as well as pure TiO2 under simulated sunlight irradiation. Even if sunlight was used for irradiation (sunshine at 10 am on September 17, Beijing time, which was a cloudy day, and the temperature was 27 degrees C), the SnS2/TiO2 sample could still effectively degrade methyl orange (MO). In this decontamination process, MO was first reduced by the electron and then subjected to oxidation by the h(+)-generated center dot OH. Alternatively, MO could be directly oxidized by center dot OH. Apart from MO, SnS2/TiO2 composites could also be applied to effectively remove other contaminants, such as methyl blue (MB) and phenol. In summary, the prepared SnS2/TiO2 is a promising photo-catalyst for practical applications in decontamination.