Research On Microstructure And Optical Properties Of Nano-TiO₂ Composite

TiO₂,an important inorganic semiconductor material has gained considerable attention in the scientific and industrial community due to its unique features such as large band gap,low cost and non-toxicity,which make it a suitable material for a variety of applications such as in the photo-catalytic and ultrasonic catalysis.However,in spite of interesting properties,TiO₂ in its pure form,shows large electron-hole recombination affinity,lower efficiency in solar energy conversion as well as in the photo-catalytic process.So far,numerous efforts have been devoted to tailor its properties for the improved role of the materials in the above mentioned applications.It is expected that integration of TiO₂ with other materials,in the form of a well defined composite nanostructure,might provide an opportunity for the fabrication and development of new TiO₂-based hybrid devices.So,here we introduce a novel composite nanostructure based on three materials,TiO₂,ZnO,and MoS₂,which could improve the absorption of visible light and promote the separation of photo-generated hole of the composite materials.In this paper,a ZnO-MoS₂-TiO₂ based nanocomposite is regarded as the main research objective,and its preparation,investigation of structural,photoluminescence,light absorption and other related properties were investigated comprehensively.The outlines of conducted work and final achievements are listed as follows:?1?The ZnO-MoS₂ nanocomposites were prepared by hydrothermal method which used the ZnO nanorods as the core and MoS₂ as the shells.The effect of MoS₂,sample's preparation temperature on the morphology,crystal structure,light absorption and photoluminescence properties were studied.After the combination of ZnO and MoS₂,the absorption of visible light is found to be enhanced and the photoluminescence intensity is weakened by UV excitation.Under the visible light excitation,the photoluminescence intensity of some samples reaches a saturation level with the increase of excitation power.The mechanism of photoluminescence is also discussed.It is concluded that the defects,the separation of photogenerated electron holes at the interface and the temperature of the samples play an important role in the achievement of desired photoluminescence properties.?2?TiO₂ coating was grown on ZnO nanorods and ZnO-MoS₂ nanocomposites by sol-gel method.Therefore,ZnO-TiO₂ and ZnO-MoS₂-TiO₂ nanocomposites were obtained.The crystal structure,morphology,composition,light absorption and photoluminescence properties of the samples were studied.Compared with ZnO-MoS₂,the photoluminescence intensity of ZnO-MoS₂-TiO₂ nanocomposite samples is enhanced remarkably,which may be attributed to the separation of electron-hole pairs in the interface between TiO₂ and MoS₂.The separation of electron hole pairs at the interface between ZnO and MoS₂ was suppressed.?3?The microstructure and degradation performance of Ni-doped TiO₂ and ZnO-TiO₂ nanocomposites under the ultrasonic wave was also studied.By changing the ultrasonic frequency and ultrasonic time,it was found that the degradation performance of ZnO-TiO₂ was the best.