Bismuth Tungstate Composite Photocatalyst Preparation by Solvothermal Method

Bismuth tungstate is a star product in the field of photocatalyst. Because of its narrow forbidden band width (about 2.7eV), it can respond to visible light of 400-460 nm, and because of the layered characteristics of Bi₂WO₆ structure, which consist of WO₆ eight surface layer and Bi₂O₂ layer alternately.

It makes it easy to form 3D superstructure assembled by nanosheets, which not only provides more sites for photocatalytic reaction, but also has better recycling performance, which shows potential application in environmental purification. Although Bi₂WO₆ is more capable of using solar energy than traditional photocatalyst TiO₂, but due to its intrinsic absorption threshold (460nm), the pure bismuth tungstate photocatalyst still has some bottlenecks that limit its practical application. One is that the absorption range of visible light is narrower, and the two is that the recombination rate of the photogenerated carrier is faster. The construction of heterogeneous structures is one of the ways to effectively solve the above problems. Therefore, Zhang Guoying and other scholars put forward the idea of bismuth overmodified Bi₂WO₆. By utilizing the hydrolysis characteristic of Bi source, using only one kind of bismuth source and making it excessive, a Bi (OH)₃ composite Bi₂WO₆ heterogeneous photocatalyst was prepared by one pot solvothermal method.

Preparation of bismuth hydroxide / bismuth tungstate Bi (OH) ₃ / Bi₂WO₆ composite photocatalyst by solvothermal method, compared with the pure Bi₂WO₆ prepared by the measurement of Bi and W, the activity of the composite photocatalyst is significantly improved. Bi(OH)₃/Bi₂WO₆ composite photocatalyst in the degradation of dye wastewater, saccharin wastewater and papermaking wastewater showed high photocatalytic properties, and compared with Bi₂WO₆ photocatalyst composite titanium, silver and other elements, the process has advantages of simple structure, low cost, high product performance, strong circulation, it can effectively solve the bottleneck problem of Bi₂WO₆ photocatalyst faced in practical application. 

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