Settlement Bi < Sub > 2 < / Sub > < Sub > 6 < / Sub > And Bi < Sub > 2 < / Sub > Send < Sub > 6 < / Sub > / Tio < Sub > 2 < / Sub > Heterojunction Preparation And Photocatalytic Performance Of The Research

TiO₂is one of the traditional photocatalytic materials and in order to solvethe problem of TiO₂photocatalyst has lower utilization of natural light with aband gap wider; on the other hand, TiO₂photo-carrier recombination rate ishigher, resulting in low quantum efficiency.. This paper develop newsemiconductor photocatalysts responding to visible light that study Bi₂WO₆and Bi₂WO₆-TiO₂photocatalysts and photocatalytic properties. The maincontents include the following aspects.Using HNO3、NaOH and NH₃·H₂O adjust Bi₂WO₆polymeric pecursorsolution pH values prepared Bi₂WO₆nano-powder by Hydrothermal method,Different morphology and photocatalytic performance of Bi₂WO₆are synthesized.We chose the pH=3,7,11as a typical acidic, neutral and alkaline conditions toexplore the pH’s influence on the Bi₂WO₆powder. The structure, surfacemorphology and photocatalytic properties of the samples have been analyzedand characterized by scanning electron microscope （SEM）, X-ray diffraction（XRD）, UV-Vis spectrophotometer. The results indicate that lamellar structureand the bird’s nest structure of Bi₂WO₆powder were synthesized when pH=3and7, octahedral particles Bi_3.84W_0.16O_6.24was synthesized when pH=11. Theirphotocatalytic activities have a great difference and pH=3> pH=7> pH=11This paper studies a Bi₂WO₆/TiO₂photocatalytic powders andphotocatalytic properties. The different proportions of TiO₂and Bi₂WO₆is beenmade Bi₂WO₆/TiO₂nano-powder by Hydrothermal Synthesis. The experimentalresults show that: Doping TiO₂can improve Bi₂WO₆photocatalytic properties;Bi₂WO₆/TiO₂photocatalytic principle of photocatalytic powder follows acollaborative mechanism, which can resovle the problem of TiO₂semiconductorband gap width and Bi₂WO₆poor photocatalytic performance. The dopingquantity of TiO₂has a great influence on morphology of Bi₂WO₆/TiO₂photocatalytic powder. According to join different the TiO₂mass fraction ournotes for TiχBW. When TiO₂is doped with lower amount, it shows ball-flower;While with higher amount, it shows synusia. Excellent photocatalytic properties have been showed in the visible light, and the catalytic efficiency isTi30BW>Ti10BW>Ti20BW>Ti40BW>Ti50BW.Bi₂WO₆precursor solution was prepared with different mass fraction（1wt%,2wt%,3wt%,4wt%and5wt%） by amorphous complex and viadipping-coating prepared thin film on glass substrates. Different mass fraction ofsingle and double Bi₂WO₆films peparation to explore the affect of the precursorsolution mass fraction and membrane layers for photocatalytic properties.Experiments show that the mass fraction of3wt%of the monolayer thephotocatalytic activity of Bi₂WO₆film best and degradation rate was29.16%after irradiating14h. Photocatalytic activities of single Bi₂WO₆film is betterthan the double films for the same mass fraction of Bi₂WO₆precursor solution.Selecting the mass fraction of3wt%of the Bi₂WO₆film calcined at differenttemperatures to explore the calcination temperature on the photocatalyticperformance of the Bi₂WO₆film, the results show that calcination temperature is350℃have best catalytic activity and degradation rate was50.68%afterirradiating14h.TiO₂sol had been prepared by sol-gel method, Bi₂WO₆precursor solutionwas successfully synthesized via amorphous complex method. Bi₂WO₆/TiO₂heterojunction films were prepared by dip-coating technique, and then theeffects of heat treatment temperature、 the order of coating and Bi₂WO₆polymeric pecursor solution on the morphology, structure and photocatalyticactivities of the films were investigated. Glass/Bi₂WO₆/TiO₂heterojunction filmforms interesting surface of the porous structure and increases the specificsurface area of membrane. The mass fraction of1wt%precursor solution of theGlass/Bi₂WO₆/TiO₂heterojunction film has the highest photocatalytic activityand degradation rate was80.67%after irradiating14h. monolayer TiO₂thinfilm degradation efficiency was43.64%after irradiating14h.