SnS₂and TiO₂Composites Prepared By Hydrothermal Method And Their Photo Catalytic Properties

Pollution caused by emissions from organic waste water of medicine, dyes, bilchemical and other industrial sectors has been a serious threat to the survival of the human environment. Using the traditional treatment such as biological, physical and chemical treatment methods can not fundamentally eliminate pollutants, while photocatalytic degradation technology can use the inexhaustible solar energy to degradate the organic matter to non-toxic CO2and H2O. However, on the one hand, the photocatalytic activity is limited by the wide energy band gap (Eg≥3.2eV) which can only use the ultraviolet light. On the other hand, the photocatalytic activity is limited by the high recombination rate of photo-induced electron-hole pairs formed in photocatalytic processes. In this paper, the simple and rapid hydrothermal method has been used to synthesize the nano-sized TiO2-based catalyst in order to maximize the utilization of the visible light and reduce the recombination of electrone hole. The main research content of this paper is as follows:(1) The particles of TiO2modified with various amounts of SnS2nanoparticles (TiO2/SnS2) were synthesized via the hydrothermal method by reacting SnCl4·5H2O with thioacetamide in5%(vol.) acetic acid aqueous solution in the presence of TiO2. The obtained products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron, transmission electron microscopy and UV-vis diffuse reflection spectra. The photodegradation activities of TiO2/SnS2composites have also been investigated under the light irradiation of250-400,360-600and400-600nm by using methyl orange as target in water. It was found that the photodegradation activity of TiO2/SnS2composites depended on the mass ratio of SnS2and the wavelength of the irradiating light. The composites containing33%SnS2exhibited the highest activity under the light irradiation of250-400and360-600nm. However, the more SnS2in the composites, the higher activity appeared under the400-600nm light irradiation. All the studies reveal that the composites possess much better activity than the single TiO2.(2) The nano-sized SnS2modified with rutile TiO2(SnS2/TiO2) were prepared through the hydrothermal treatment of TiCl3in the presence of SnS2at160℃for4h. The samples have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy and UV-vis spectroscopy. The photodegradation of methyl orange (MO) has been investigated under the light irradiation of360-600and400-600nm by using the samples as photocatalyst. The results demonstrated that the photocatalytic activities of the as-prepared SnS2/TiO2depended on the content of TiO2, and SnS2/TiO2containing26%TiO2displayed the optimum activity which is much larger than that of pure SnS2, while the rutile TiO2has almost not the activity for the MO degradation.