Study On The Preparation Of TiO₂-based Nanofibers And The Performance Of Catalytic Degradation Of Toluene

At present,photocatalytic technology as an economical,effective and environmentally friendly method of catalytic toluene has become a research hotspot for the removal of atmospheric pollutants.Titanium dioxide photocatalyst is widely used in photocatalytic process because of its high activity,stability,low cost and non-toxicity.Compared with TiO₂ nanoparticles,TiO₂ fibers have large specific surface area and high porosity,and the one-dimensional nanofiber structure has excellent electron transfer function.Since the electrospinning technology is simple and easy to operate and the conditions are controllable,the TiO₂ nanofibers are firstly prepared by electrospinning to catalytically degrade toluene.Secondly,in view of the problem that the photogenerated electron holes generated by TiO₂ are easily recombined during the catalytic process.Zr⁴⁺is used to dope TiO₂ to generate lattice defects,thereby the carrier recombination is supressed.Finally,due to the low sunlight utilization of TiO₂,which only 4%of the ultraviolet light in sunlight can be utilized,it causes most of the sunlight to be unused and limits its wide application.However,about 50%of the near-infrared light in sunlight is not utilized.Because of near-infrared light excellent thermal effect,it can be combined with thermal catalyst manganese dioxide in TiO₂ for photothermal synergistic catalysis.Thereby it can make full use of sunlight and improve its catalytic efficiency.In order to solve the above problems,firstly TiO₂fiber was prepared by simple and easy-to-operate electrospinning technology,and then improves its catalytic performance and application by Zr⁴⁺doping and MnO₂semiconductor compounding.The main research contents are as follows:?1?Titanium dioxide fibers were prepared from tetrabutyl titanate,ethanol and acetic acid by electrospinning and calcination at high temperature.Besides it is characterized by corresponding instruments.XRD and SEM analysis showed that the crystal form of anatase titanium dioxide was smooth and fibrous and the diameter of the fiber was about 200 nm.?2?Zr⁴⁺doped titanium dioxide fibers with different content were synthetised by electrospinning technology and the corresponding characterization and testing were carried out.The results of XRD,XPS and TEM characterization showed that Zr⁴⁺entered into the lattice of titanium dioxide and the crystal form remained unchanged.Besides the surface of Zr⁴⁺is smoother and the diameter of the fiber was increased to about 300 nm.The results of catalytic test showed that5Zr-titanium dioxide fiber had the best catalytic performance.Moreover,the toluene mineralization rate could reach 94.21%after 6 hours of full spectrum illumination,which was 10.85%higher than that of pure titanium dioxide fiber.Through PL analysis,we can know that the fluorescence intensity is the lowest,indicating that the electron hole pair is the easiest to separate,so its catalytic activity show the best performance.Because the radius of Zr⁴⁺is similar to that of Ti⁴⁺,it is easy to enter into the lattice of titanium dioxide,resulting in lattice defects which trap electrons and improve the separation efficiency of electron hole pairs.Thus it can enhance their catalytic activity.?3?MnO₂/5Zr-TiO₂ composite fibers were prepared by in-situ precipitation and loading of MnO₂ in different proportions on 5Zr-TiO₂ fibers.Among them,3MnO₂/5Zr-TiO₂ has the best catalytic performanceand the toluene mineralization rate can reach 100%after 2 hours of fullspectrum illumination.Compared with 5Zr-titanium dioxide fiber,the catalytic activity was increased to42.13%.The material combined the advantages of photocatalysis and thermal catalysis and made full use of sunlight,which ultraviolet light photocatalysis and near infrared thermal catalysis can significantly improve its catalytic effect,save energy and make it have broad application prospects.In order to improve the catalytic activity of TiO₂ fibers by Zr⁴⁺and MnO₂semiconductor composites,it is aimed at improving the practical application value of TiO₂ fibers in the field of air purification.