Preparation Of TiO₂-based Composite Micro-nano Fibers And Their Photocatalytic Degradation Performance

In recent years,water pollution has become increasingly serious.As a kind of semiconductor catalyst with excellent performance,TiO₂ has many important applications in the field of photocatalysis.Utilizing the photocatalytic effect of TiO₂,the organic pollutants can be degraded into non-toxic and harmless small molecular substances such as H₂O and CO₂ by the ultraviolet part of the light.This provides a new way to solve the problem of water pollution.However,TiO₂ nanoparticles are easy to agglomerate,which greatly reduces their photocatalytic degradation efficiency.In this paper,TiO₂ or tetrabutyl titanate was mixed into the spinning solution using electrospinning technology with cellulose acetate（CA）as the raw material.Nanofibers reduce their agglomeration performance and improve photocatalytic degradation efficiency.The method of directly mixing TiO₂ nanoparticles was used to prepare TiO₂-supported micro-nano fibers（TiO₂/CAFM）.Scanning electron microscope test results show that TiO₂ is uniformly distributed on the fiber filaments and has a good micro-morphology.The photocatalytic degradation performance test was performed under visible light and ultraviolet light.The results showed that methylene blue dye（MB）had better photocatalytic degradation under TiO₂/CAFM ultraviolet light,and the degradation rate could reach 99.4%in 120 min.The larger the TiO₂ content;when the p H value is 9,it has better photocatalytic degradation performance,and the higher the TiO₂ content on TiO₂/CAFM,the higher the photocatalytic degradation rate;when the catalyst content is the same,the degradation rate gradually decreases with the increase of the initial concentration,and the degradation rate can reach 99.4%when the initial concentration of the solution is 10 mg/L.Because TiO₂/CAFM has strong hydrophilicity,it cannot be recycled many times.Using tetrabutyl titanate（TBT）as the titanium source,TiO₂ precursor micro-nano fibers（TBTFM）were prepared,and carbon-doped TiO₂ composite micro-nano fibers（C/TiO₂FM）were obtained by calcining TBTFM.XRD test results show that the TiO₂ crystal form on the C/TiO₂FM is anatase.The photocatalytic degradation performance test results show that C/TiO₂FM is capable of photocatalytic degradation of MB under both visible and ultraviolet light.Under two different light sources,the larger the TBT content in the C/TiO₂FM precursor solution,the better the photocatalytic degradation performance;when the catalyst content is the same,the photocatalytic degradation rate gradually decreases with the initial concentration of the solution,when the initial concentration of the solution is 10 mg/L,the degradation rates under UV and visible light are 99.9%and 86.7%,respectively.When the experiment time is extended to 5 h and the initial concentration of the solution is 50 mg/L,the degradation rate under visible light can reach 99.9%;In addition,C/TiO₂FM can be recycled multiple times,effectively improving the utilization rate of materials.