Photocatalytic Degradation Of Rhodamine B By Bismuth Tungstate Based Composite Materials

The use of semiconductors for photocatalytic reactions has been widely concerned.Bismuth tungstate?Bi₂WO₆?is a promising catalyst in the study of various photocatalysts,because it can decompose water to produce oxygen?O₂?and decompose organic pollutants in visible light.However,pure Bi₂WO₆ catalyst has low utilization rate of solar energy,high photogenerated electron-hole recombination rate and low quantum efficiency,which limit its application.In recent years,many studies have been devoted to improving the photocatalytic activity of Bi₂WO₆ and achieving higher photocatalytic efficiency.In this paper,Bi₂WO₆ was modified by three methods,and the modified photocatalyst was characterized by X-ray diffraction,infrared spectrum,scanning electron microscope,UV-vis diffuse reflectance spectrum and photoluminescence spectrum.The performance of photocatalyst was evaluated by degradation of rhodamine B,and the photocatalytic reaction process was explored.?1?Bi₂WO₆ microparticle photocatalyst was successfully synthesized by hydrothermal preparation of carbonaceous polysaccharide spheres as templates.The results showed that the photocatalytic performance of granular Bi₂WO₆ was significantly better than that of bulk Bi₂WO₆.The adhesion of Bi₂WO₆ particles increases the specific surface area and has a larger adsorption capacity.The small amount of carbon in the Bi₂WO₆/C heterojunction inhibits the combination of photogenerated electrons and holes.?2?Bi₂WO₆/BHN composite photocatalyst modified by BHN was prepared by hydrothermal method.According to the analysis of experimental data,the migration ability of electrons is enhanced and the separation of photogenic electrons and holes is promoted because of constructing heterogeneous junction.The introduction of BHN effectively enhanced the photocatalytic activity of Bi₂WO₆ for rhodamine B degradation.The experimental results showed that the optimum BHN composite amount was 0.05 g and the photocatalytic rate was the fastest.?3?Cu/Bi₂WO₆ photocatalyst was prepared by two-step hydrothermal method.The results showed that Cu²⁺was reduced to Cu by ethylene glycol and loaded on the surface of bismuth tungstate.Compared with pure Bi₂WO₆,Cu/Bi₂WO₆ has stronger visible light absorption and higher utilization rate of photo-generated carrier.When the Cu content was1.0%,the photocatalytic activity of Cu/Bi₂WO₆ composite was the best.