Prepration,Modification Of Fibrous SO₄^2-/TiO₂ And Its Application In Photocatalytic Degradation

TiO₂ photocatalyst has become the research hotspots in the field of photocatalysis for a long time,and is expected to be one of the most promising green-type catalyst because it has many advantages,such as low-cost preparation,non-toxic,anti-light corrosion and chemical stability,etc.There are two factors that decrease the efficiency of TiO₂ catalyst.One is poor adsorption on target pollutant,the other is certain combination of photo-generated electron（e^-）and hole（h⁺）.Therefore,it is necessary to prepare and modify fibrous TiO₂ in order to improve the photo-catalytic performance,which was discussed in this thesis.（1）Based on the data obtained from the SEM,TG,XRD,N₂-desorption-adsorption,and UV-Vis analysis,mesoporous structure fibrous TiO₂was synthesized with collagen fibers,a natural polymer as template with the best material ratio of 8:5,the optimum calcination temperature is 600℃,the TiO₂ can be maintained as an anatase crystalline when the template is completely removed.The grain size of TiO₂ is 11.8 nm and the specific surface area increases to 114.86 m2/g.Compared with powdered TiO₂,fibrous TiO₂ exhibits better photocatalytic performance in the photocatalytic reaction with phenol.（2）SO₄^2-/TiO₂ photocatalyst was obtained by modifying based on the analysis results of IR,XRD,XPS,UV-Vis etc.,we can conclude that the grain size decreases and the quantum size effect With the increase of the width,the photo-generated electrons and the redox capacity of the holes increase,thus SO₄^2-/TiO₂ has relatively strong photoresponsive ability in the ultraviolet region.And the optimum activation temperature is 300℃.Compared with TiO₂,the degradation rate of SO₄^2-/TiO₂ to phenol was 82.86%under UV irradiation.（3）SO₄^2-/TiO₂-Nd was prepared with SO₄^2-/TiO₂ and rare earth ions Nd³⁺.The prepared SO₄^2-/TiO₂-Nd was characterized by SEM,UV-Vis and XPS.When Nd³⁺was added,the prepared photocatalyst kept the fiber structure still.Nd³⁺can form Ti-O-Nd bond with,so when the electron cloud density of Ti decreases,and the energy difference between the band of SO₄^2-/TiO₂ is 5eV,the surface chemical properties are changed and the electron-deficient properties of Ti can be enhanced.With better oxygen adsorption in the reaction system,target pollutants and other particles can be adsorbed on the surface of the catalyst,thus it is helpful for the formation of oxygen holes,which is the key to the formation of·OH.With the impurity energy level introduced,the band gap of SO₄^2-/TiO₂-Nd is reduced,the number of electrons and the photon utilization efficiency of the catalyst are increased,and the photocatalytic performance is enhanced.（4）Glyphosate（organophosphorus pesticide）and nitrobenzene（nitrobenzene）were listed in selected as the target pollutants in the list of water pollutants in China,and their photocatalytic degradation was carried out.The effects of catalyst addition,reaction temperature,reaction time and initial pH on the degradation rate were investigated.During the photocatalytic reaction,SO₄^2-/TiO₂-Nd exhibited relatively strong catalytic performance.