Preparation And Photocatalysis Research Of Photocatalyst Based On TiO₂

TiO₂ nanomaterials is widely used in photocatalytic degradation of pollutants in water because of its excellent physicochemical properties（stability,non-toxicity and high catalytic activity）.However,it has absorption only in the ultraviolet region（200-400nm）,which limits its catalytic performance in visible light.Therefore,based on TiO₂,different composite catalysts were prepared by semiconductor composite modification.XRD,SEM,UV-vis DRS,BET and photocurrent were used to characterize and analyze the catalysts,and their catalytic degradation performance in visible light was discussed by photocatalytic experiments.The specific experimental results are as follows:（1）The TiO₂ nanomaterials were prepared by hydrothermal,microwave,sol-gel and electrospinning methods,respectively.The effect of the preparation method on the performance of the catalysts was investigated.The characterization results show that anatase TiO₂ can be successfully prepared by four methods,and the forbidden band width is around 3.10eV.however,TiO₂ nanofibers prepared by electrospinning have regular and uniform fiber morphology,larger specific surface area of 40.79 m²/g and better catalytic performance,the optimum reaction conditions of electrospinning were further investigated.The spinning distance was 12 cm,the spinning voltage was 10 kv,the spinning speed was 1.2 ml/h,and the heating rate was 1℃/min.when calcined in muffle furnace at 550℃ for 1h,the photocatalytic effect of TiO₂ nanofibers was the best.Under the irradiation of mercury lamp,the degradation rate of MB solution could reach 98.9% within 120 min.（2）In order to improve the absorption of TiO₂ nanofibers in visible light,MoS2/TiO₂ composite photocatalyst was prepared by hydrothermal method.The results showed that the specific surface area increased to 104.69 m2/g and the forbidden band width decreased to 2.90 eV.The optimum conditions for preparing reaction,when the complex amount of MOS₂ is 15%,the hydrothermal reaction time is 20h,and the hydrothermal reaction temperature is 200℃,the prepared MoS₂/TiO₂ composite photocatalyst has the highest activity,and the degradation rate of MB reaches 96.4% within 60 min under xenon lamp irradiation,the degradation rate of RhB and Tc reaches 98.7%and and 82.2%,respectively,under the same conditions.（3）In order to facilitate the recycling of catalyst,magnetic fe₂O₃ material was introduced into MoS₂/TiO₂,and MoS₂/TiO₂/Fe₂O₃ composite fibers was prepared by electrostatic spinning method.The results showed that the specific surface area increased to 68.59 m2/g and the forbidden band width decreased to 2.21 eV.The optimal sample degraded MB by 98.3% within 60 min under xenon lamp irradiation,and the degradation rate remained above 98% after being reused for 5 times.The degradation rate of Tc reached 86.9%under the same reaction conditions.