Preparation And Photocatalytic Property Of Hierarchical Porous Structures TiO₂-Based Nanocomposites

With the rapid development of China’s printing and dyeing industry,both the output of dyes and the export trade are ranked first in the world.At the same time,economic development has caused serious damage to the ecological environment.Dye wastewater mainly comes from the loss of dye products and dye production process and the washing equipment wastewater.Due to the lack of strict management and discharge mechanism,a large amount of wastewater is not processed into the water body.Compared with traditional water treatment technologies,photocatalytic technology has become a research hotspot for researchers because of its high degradation efficiency of pollutants,no secondary pollution and low energy consumption.Titanium dioxide nanomaterials as a research hotspot of scholars,in addition to the advantages of other catalytic materials,but also has the advantages of cheap,easy to obtain,easy to prepare.In this dissertation,TiO₂ with hierarchical porous structure was prepared by using straw as biological template.In order to improve its photocatalytic performance,Bi2 Mo O6/TiO₂ composite and Bi2WO6 / TiO₂ composite were prepared by simple hydrothermal method of doping Bi2 Mo O6 and Bi2WO6.Using xenon lamp as a light source,Rhodamine B was used as a photodegradation pollutant to evaluate the photocatalytic activity of the catalyst material,and the best composite catalyst material system was selected according to the experimental results.Finally,SEM,TEM,XRD,XPS,FT-IR,UV-vis DRS and SPS were used to analyze the catalyst materials.The results showed that Bi2 Mo O6 and Bi2WO6 were doped into TiO₂ with a graded porous structure to form Bi2 Mo O6/ TiO₂ composites and Bi2WO6 / TiO₂ composites.Their photocatalytic activity was better than that of pure phase TiO₂,Bi2 Mo O6 and Bi2WO6.Improved significantly.The optimum doping ratio of Bi2 Mo O6/ TiO₂ composite material is 0.3 mol/mol,which can degrade the 10mg/Ldye completely within 90 minutes,while the optimal doping ratio of Bi2WO6 / TiO₂ composite material is 0.5 mol/mol.Degradation of the 20 mg/L dye was complete within 75 minutes.Through the doping of two kinds of semiconductors,the composite material forms a heterostructure,which is advantageous to inhibit the recombination of electron-hole pairs,and to a great extent enhance the photocatalytic reaction activity of the composite material.