Synthesis And Photocatalytic Property Of Sulfur-doped Titanium Dioxide Photocatalyst

Photocatalysis was a potential technology in solving the problem of waste water due toits unique advantages. Along with the widely use of photocatalysis, photocatalysts withsuperior properties have became a hot research topic. TiO2has been considered as one ofthe most important photocatalysts since it possesses many advantages, such as nontoxicity,low cost, long-term stability and excellent chemical stability. However, there are still someshortcomings inhibiting the practical utilization of TiO2, for instance the large band gap,which result in the partically utilization of the solar energy. In order to overcome thisproblem, a series of researches have been reported. Among these methods, modified TiO2have been considered as one of the most effect ways.In this paper, the ZnO/TiO2composite has been successfully synthesized by the sol-gelmethod. The samples were characterized by XRD, TEM and DRS techniques. A seires ofpreparation conditions, including ZnO doping mole proportion, calcination temperature andtime, were investigated on the degradation of the Reactive Brilliant Red X-3B solutionunder UV light and simulated sunlight irradiation. The results showed that the as-preparedTiO2were mainly composed of anatase nanocrystalline, influenced by the calcinationtemperature. It is clearly seen that there was a red-shift of absorption edge for the ZnO/TiO2composite. It is found that the ZnO/TiO2composite with the ZnO doping mole proportion of4%(Zn:Ti), calcined at500℃for2h gave the best photocatalytic behaviors. On theoptimal conditions, the degradation rate of Reactive Brilliant Red X-3B (20mg/L) underUV light and simulated sunlight irradiation reached99.6%and79.9%respectively.The S/ZnO/TiO2photocatalyst was also prepared by the sol-gel method. Themorphology, structure and optical properties of the samples were characterized by XRD,TEM, DRS, EDS, XPS and PL. The preparation conditions, including S doping moleproportion, calcination temperature and time, were investigated on the degradation of theReactive Brilliant Red X-3B solution under simulated sunlight. The results showed that thecomposites were mainly composed of anatase and S-doping led to the local distortion of thecrystal. In comparion with ZnO/TiO2composite，the S/ZnO/TiO2photocatalyst exhibitedmore pronounced red-shift and stronger absorption in visible light region. S element in the composite was present as the form of S4+and S6+. It is found that the S/ZnO/TiO2compositewith the S doping mole proportion of16%(S:Ti), calcined at500℃for2h gave the bestphotocatalytic behaviors. Meanwhile, the optimum dosage of S/ZnO/TiO2was1g/L.Moreover, there was no obvious decrease of the photocatalytic activity of the catalyst afterrecycling the catalyst for three times and the degradation rate all reached more than50%.It is worth noting that zinc nitrate hyexahdrate are benefit for the preparation ofphotocatalyst with better performance in this case.