Preparation Of TiO₂ Nanofiber Membrane Supported Pt And Its Degradation Of Dyeing Dyes

As a green,energy-saving and environmental protection technology,As a green,energy-saving and environmental protection technology,photocatalytic technology has great development potential.With the in-depth research of photocatalytic technology by researchers,the level of photocatalytic technology has been continuously improved and improved,and has increasingly become the focus of attention in people’s vision.TiO₂ itself has the advantages of non toxicity,stable physical and chemical properties and low cost,and TiO₂ itself has strong oxidation ability.Under the condition of receiving external light,it can decompose harmful substances in the environment into H₂O and CO₂.Therefore,it is often used as a photocatalyst in the field of photocatalysis.There are many forms of TiO₂.The common TiO₂ exists in the form of particles and powder.However,the use of granular and powder TiO₂ in the field of photocatalysis has many disadvantages,such as easy agglomeration,non recyclability,secondary pollution and low activity,which leads to the limited application of granular and powder TiO₂ in the field of catalysis.Self supporting TiO₂ film can overcome the above defects and has attracted extensive attention of researchers.However,it often needs to be modified.Due to the wide band gap of unmodified TiO₂（Eg=2.9e V-3.3e V）,the photogenerated electrons and electron holes generated by photocatalysis are very easy to compound,and pure TiO₂ can only absorb ultraviolet light with wavelength less than 400nm and can not show activity under visible light greater than 400nm,which greatly reduces the efficiency of TiO₂ in using natural energy（utilization rate≈5%）.In order to solve the above problems,this paper has carried out the following research work:（1）In order to prepare TiO₂ nanofiber films with better mechanical properties,two kinds of TiO₂nanofiber films were prepared with PVP and PEO as polymer templates respectively.The elements,crystal form and morphology of TiO₂ nanofiber films were characterized and tested,and compared with P25 titanium dioxide powder widely used in the field of photocatalytic degradation,The results showed that the TiO₂nanofiber membrane prepared with PEO as template had better photocatalytic degradation performance.Under UV irradiation,10mg PEO/Ti O2 nanofiber membrane can degrade 100m L malachite green dye with a concentration of 50mg/L within 2h.（2）In order to improve the degradation activity of TiO₂ fiber under visible light,the TiO₂nanofiber membrane was modified by loading precious metal Pt.The TiO₂nanofiber membrane prepared by electrospinning was used as the base material and chloroplatinic acid solution was used as the modification solution.The TiO₂ nanofiber membrane was modified by sodium borohydride thermal reduction method.A series of characterization tests were carried out on the obtained Pt-TiO₂ nanofiber film,which confirmed that Pt particles were stably and evenly loaded on the surface of TiO₂ nanofibers,and the band gap of Pt-TiO₂ nanofiber film was significantly reduced（Eg=2.6e V）.（3）In order to study the photocatalytic degradation performance of the above fiber membrane,the degradation effects of Pt-TiO₂ nanofiber membrane on three dye solutions（malachite green dye,brilliant green dye and basic fuchsin dye）under three external conditions of darkness,ultraviolet light and visible light were tested.It was unexpectedly found that Pt-TiO₂ nanofiber membrane could have a strong adsorption effect on three dye solutions under dark conditions,and it was also found that under visible light,Pt-TiO₂ nanofiber membrane can show high degradation activity.100ml malachite green dye with a concentration of 50mg/L can be degraded within 1h.