Synthesis And Study On Catalytic Activity Enhancement Of Titanium Dioxide Photocatalytic Material With Microsphere/Microrod Structure

In the past few decades,titanium dioxide(TiO2)has proved to be one of the most promising photocatalysts for environmental applications.However,TiO2 has suffered from many limitations in practical applications,such as narrow response spectrum(which can only absorb ultraviolet light),low quantum efficiency,and difficulty in recycling.In order to solve the above problems comprehensively,this thesis carried out the preparation and modification research of TiO2 catalyst,using tetrabutyl titanate as the titanium source,designing a relatively simple synthesis method,and preparing two kinds of TiO2 microstructure materials:micrometer TiO2 hollow ball and TiO2 nanorod array film.The photocatalytic performance of the prepared TiO2 microstructure was modified in different forms(composite semiconductor structure,precious metal deposition,surface quantum dot sensitization).The main work and conclusions of the thesis are as follows:1)First,two microstructures of micrometer-scale hollow sphere TiO2 and nanorod array TiO2 were prepared.The diameter of TiO2 hollow microsphere is about 3.97 μm,which solves the problem of difficulty in recycling powder photocatalyst,and the hollow structure on the surface of microsphere is photocatalysis.The reaction provides more reaction sites,and at the same time enhances the reflection/scattering of light and improves the light absorption efficiency.The aspect ratio of the nanorod array TiO2 is about 17,the ordered arrangement structure promotes the photoelectron transmission efficiency,and the increased specific surface area enhances the adsorption capacity of organic matter.2)On the basis of TiO2 hollow microspheres,Cu2O/C@H-TiO2 nanocomposites with enhanced visible light photocatalytic activity were synthesized by one-pot method.The formation of a heterojunction on the interface between TiO2 and Cu2O can effectively separate photogenerated electron-hole pairs.Due to the visible light absorption of Cu2O,the response spectrum of the sample is expanded.As a concomitant product of the Cu2O reduction reaction,amorphous carbon can further improve the electronic conduction characteristics between Cu2O and TiO2.The experimental results of the degradation of methylene blue(MB)aqueous solution show that the degradation efficiency of Cu2O/C@H-TiO2 nanocomposites is about 3 times that of pure TiO2 hollow microspheres,and more complete degradation is possible.3)Modification study of TiO2 nanorod array film catalyst.Gold nanoparticles(Au NPs about 5 nm)and carbon quantum dots(CQDs:7～8 nm)are used as dual promoters to modify the surface of TiO2 nanorod arrays(NRs)to make composite photocatalyst films:Au/CQDs-TiO2 NRs.Due to the presence of surface plasmon resonance(SPR)and CQDs of Au nanoparticles on the surface of TiO2 NRs,the recombination of electrons is suppressed,the absorption of visible light is expanded,and the electron transport performance is improved.Photoelectrochemical studies have shown that the photocurrent of Au/CQDs-TiO2 NRs composite film is about 4 times higher than that of pure TiO2 NRs film.As a basic photoelectric conversion material,TiO2 and its composite materials provide new ideas and solutions for the preparation of high-efficiency photocatalysts.At the same time,they have great application prospects in optical biosensors,solar cells,photoelectric conversion capacitors and other photoelectric devices.