Study On Preparation And Photocatalytic Properties Of Doped TiO₂ Nanofibers

In recent years,photocatalytic technology has attracted much attention in solving energy crisis and dealing with environmental pollution.As a semiconductor catalytic material,TiO₂ plays an extremely important role in the field of photocatalysis due to its stable chemical properties,corrosion resistance and non-secondary pollution.However,due to the wide band gap width?3.0-3.2e V?,the low utilization rate of sunlight?only able to absorb 4%of ultraviolet light?and the fast recombination of photogenic carriers,TiO₂ limited its application scope.In order to overcome the limitations of TiO₂,the modification of TiO₂ has become a research hotspot.In this paper,TiO₂ nanofibers with different doping modification were prepared by combining electrostatic spinning technology with calcination process and modification methods of nonmetal doping,metal doping and co-doping.The photocatalytic performance of various doped TiO₂ nanofibers was studied and the photocatalytic mechanism was further discussed.The main work of this paper is as follows:?1?TiO₂ nanofibers were prepared by electrostatic spinning method,and the effects of calcination temperature and light source on the photocatalytic performance of TiO₂ nanofibers were studied.XRD analysis shows that the calcination temperature determines the crystalline structure of TiO₂.DRS analysis showed that the band gap width of TiO₂ samples prepared by calcining at 600?was narrowed and the absorption bandwidth was extended to the visible light region of 420nm.Photocatalytic studies show that TiO₂ nanofibers prepared by calcining at 600?have the best photocatalytic performance.After 150min of illumination,under the action of mercury lamp,the degradation rate of rhodamine B reached 97.5%.under the action of metal halide lamp,the degradation rate of rhodamine B was 85%.and under the action of metal halide lamp?filter?,the degradation rate of rhodamine B was 56%.?2?N-TiO₂ nanofibers were prepared by electrostatic spinning method,and the effects of calcination temperature and light source on the photocatalytic performance of N/TiO₂nanofibers were studied.XRD analysis showed that N doping increased the crystal transition temperature of TiO₂.DRS analysis showed that N doping narrowed the TiO₂ absorption band gap and extended the absorption bandwidth to the visible light region of 435nm.Photocatalytic studies show that the N-TiO₂nanofiber samples prepared by calcining at 550?have the best photocatalytic performance.After150min of illumination,under the action of mercury lamp,the degradation rate of rhodamine B was 99%,under the action of metal halide lamp,the degradation rate of rhodamine B was 94%,and under the action of the metal halide lamp?filter?,the degradation rate of rhodamine B was 77%.?3?the Ag-N-TiO₂ nanofibers were prepared by electrostatic spinning method,and the effects of calcination temperature,light source type and Ag content on the photocatalytic performance of Ag-N-TiO₂ nanofibers were studied.XRD analysis showed that Ag doping did not change the crystal structure of TiO₂,but reduced the temperature of TiO₂transition from anatase to rutile.DRS analysis showed that the sample with calcination temperature of 500?and molar ratio of n?Ag:Ti?of 3:11 had narrow band gap width and optical response range of 465nm.The photocatalysis study showed that the sample calcined at 500?and the molar ratio n?Ag:Ti?of 3:11 had the best photocatalytic performance.After 100 minutes of illumination,under the action of mercury,the degradation rate of rhodamine B was 100%.Under the action of the metal halide lamp,the degradation rate of rhodamine B was 92%,and under the action of the metal halide lamp?filter?,the degradation rate of rhodamine B was 84%.?4?Bi-TiO₂ nanofibers were prepared by electrostatic spinning method,and the effects of calcination temperature,light source type and Bi content on the photocatalytic performance of Bi-TiO₂ nanofibers were studied.XRD analysis showed that Bi doping did not change the crystal structure of TiO₂,but reduced the crystal transition temperature of TiO₂.DRS analysis showed that samples with calcination temperature of 550?and molar ratio of n?Bi:Ti?of 5:11 had narrow band gap width and optical response range extended to 460nm.The photocatalysis study showed that the samples calcined at 550?and the molar ratio n?Bi:Ti?of 5:11 had the best photocatalytic performance.After 120 minutes of illumination,under the action of mercury lamp,the degradation rate of rhodamine B was 96%.under the action of metal halide lamp,the degradation rate of rhodamine B was 90%,and under the action of metal halide lamp?filter?,the degradation rate of rhodamine B was 88%.