| With the development of economy and the improvement of people's quality of life,the demand for water quality of drinking water has been gradually improved.However,due to the serious pollution of the water body,the traditional simple treatment of the water body has not been able to ensure that the water quality can meet the requirements.Removal of pollutants from water by photocatalyst may be the trend of future development.Because of its excellent optical and physical properties,strong chemical stability,non-toxic and so on,zinc titanate has been paid more and more attention by researchers in the field of photocatalysis.However,the wide band gap of ZnTiO3 and the low utilization of solar light limit its application in the field of photocatalysis.The modified ZnTiO3 can enlarge the range of light absorption and increase the absorption of visible light,which is a very effective method to improve the photocatalytic activity of zinc titanate.This paper is based on the preparation of high catalytic activity of mesoporous ZnTiO3.In order to further improve the photocatalytic performance,mesoporous ZnTiO3-graphene composite photocatalysts were prepared.In addition,a novel heterojunction structure Ag/g-C3N4/ZnTiO3 catalyst was prepared for the visible light response,and we also explore the influence of Ag and g-C3N4 content on the photocatalytic properties.The crystal structure and optical properties of the obtained catalysts were studied by XRD,DRS.The main conclusions are as follows:(1)With tera-n-butyl titanate and Zn(NO3)2·6H2O as raw materials,ethanol as solvent,mesoporous ZnTiO3 materials were prepared by an evaporation-induced self-assembly method using polycarboxylate superplasticizer as template.A series of photocatalysis experiments have been done to study the influence of calcination temperature,time and the amount of template on the photocatalytic performance.The results show that the effect of calcination temperature on the photocatalytic performance of the sample is large,and the effect of roasting time is not too big.Considering all kinds of factors,the optimized preparation conditions is:0.4 g of template content,and baked at 500 ? for 2 h.(2)A novel mesoporous ZnTiO3/graphene composite was successfully prepared via a two-step process.The band gap of ZnTiO3/graphene composite is narrowed,and the absorption of visible light is also enhanced,when compared with the pure ZnTiO3 material.Due to graphene possessing high electrical conductivity and electron mobility,when coupled with graphene,it reduces the photoinduced electron-hole recombination rate,so the photocatalytic performance of the composite is significantly improved.The degradation rate of norfloxacin could reach 97%over the composite under visible light irradiation for 60 min,while the photocatalytic degradation rate of pure ZnTiO3 was only about 53%.(3)Based on a series of experimental study of the influence of Ag and g-C3N4 content on the photocatalytic performance,a new three element system of heterojunction structure Ag/g-C3N4/ZnTiO3 composite,with high photocatalytic activity under visible light,was prepared.The results of XRD analysis showed that the introduction of g-C3N4 and Ag did not change the structure of ZnTiO3 crystal,and the results of DRS analysis showed that either the absorption edge of the composite had a red shift or the absorption of visible light was enhanced.Under the same experimental conditions,the degradation rate of norfloxacin solution for each new composite was also significantly improved. |
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