Study On Structure Control,Luminescence And Catalytic Performance Of Eu³⁺ Doped TiO₂-SiO₂ Composite Fiber

TiO₂ has been extensively studied in photocatalytic degradation of organic pollutants such as dyes because of its low toxicity,excellent photocatalytic performance and stable chemical properties.However,TiO₂is easy to agglomerate and phase change at high temperature,and the recombination rate of electron-hole pairs is fast,which limits its development and application in the field of catalysis.Therefore,this thesis designed and synthesized rare earth doped TiO₂-SiO₂composites with certain morphology by doping SiO₂in TiO₂matrix,and explored the luminescent properties and photocatalytic performance of the materials in detail.The thesis has obtained the following research results:1.TiO₂-SiO₂-Eu³⁺composite nanofibers with different Si/Ti ratios and pure TiO₂nanofibers were prepared by electrospinning and heat treatment.Under the conditions of calcination at 600,700 and 800℃,the effects of SiO₂doping amount and calcination temperature on the crystal phase ratio of anatase and rutile,surface properties,luminescent properties and photocatalytic performance were investigated in detail.The results show that at the same calcination temperature,the luminous intensity and photocatalytic performance first increase and then decrease with the increase of Si/Ti ratio.Increasing the temperature will lead to the decrease of luminescence and photocatalytic properties of the samples.The phase comparison and crystallinity of the samples are the common factors affecting the luminescent properties and photocatalytic performance of the samples.In addition,the specific surface area and the content of Ti-O-Si bond also have certain effects on the photocatalytic properties of the samples.2.The closed cell structure of SiO₂@TiO₂:Eu³⁺was prepared by electrospinning and high temperature calcination,and the etched product of SiO₂@TiO₂:Eu³⁺was obtained by etching.The effects of sample structure,morphology,crystal phase and surface properties on the luminescent properties and catalytic activity of the materials were discussed,and the luminescent and photocatalytic properties were compared with the composite nanofibers with SiO₂-TiO₂-Eu³⁺blend structure and pure TiO₂nanofibers in detail.It is found that the closed unit structure of SiO₂@TiO₂:Eu³⁺has stronger luminescence intensity and higher photodegradation performance of methyl orange.