Study On Modification And Properties Of TiO₂ Photocatalyst

In recent years,more and more people pay attention to the problems of energy shortage and environmental pollution due to rapid expansion of industrialization.The semiconductor photocatalytic oxidation technology can provides a new way to solve these problems.Compared with the traditional methods,the semiconductor photocatalytic oxidation technology has the advantages like safety,low toxicity,complete degradation and maximum utilization of energy.TiO₂ has been considered as one of the most promising photocatalysts due to its strong oxidizing ability,light stability and relatively non toxicity.However,pure TiO₂ has a large band gap and a high probability of photoinduced charge recombination,which leads to a lower catalytic activity.In this paper,we use some modification methods to improve the photocatalytic activity of TiO₂ materials.This paper mainly deals with the following two aspects:（1）First,we have synthesized TiO₂ nanosheets using hydrofluoric acid and tetrabutyl titanate as raw materials under hydrothermal conditions.After that the synthesized TiO₂ nanosheets were used to degrade rhodamine B,methyl orange,methylene blue and methyl violet at 365 nm under UV light,in order to explore its catalytic efficiency.The TiO₂ nanosheets were characterized by XRD,TEM,FT-IR,UV-Vis,BET,XPS.Furthermore,the effect of acid on the crystal structure,morphology,bandgap and specific surface area of TiO₂ photocatalyst were analyzed by characterization datas.We found that the TiO₂ catalyst is unstable by repeated catalytic degradation of rhodamine B.In order to improve the stability of the TiO₂,the surface of the synthesized TiO₂ nanosheets were modified by 0.05 M phosphoric acid,and then the photocatalytic degradation efficiency was measured with the help of above mention four dyes.Finally,we evaluate the degradation efficiency of acid modified TiO₂ on the four dyes.（2）In the following experiment,sodium molybdate,thioacetamide and TiO₂ nanosheets were used as the precursors to synthesize the MoS₂/TiO₂ semiconductor composite with different loadings ratios of MoS₂ by the hydrothermal method.Then,the MoS₂/TiO₂ composites were characterized by XRD,SEM,TEM,FT-IR-Raman,UV-Vis,BET,XPS.Furthermore,the effect of MoS₂ on the crystal morphology,morphology,band gap and specific surface area of TiO₂ photocatalyst were analyzed by characterization data.To further explore the catalytic activity performance of the TiO₂/MoS₂ composites with different MoS₂loading ratios,the rhodamine B was used as the target material to perform the photocatalytic degradation efficiency properties.（3）The anatase TiO₂ was synthesized by the sol-gel method and then modified by nickel porphyrin compounds,the catalytic activity of these two modified TiO₂ were performed by the degradation of the rhodamine B under irradiation of Xe lamp.