Nano-flake Bismuth Tungstate Preparation by Hydrothermal Synthesis

With the rapid development of industry, more and more attention has been paid to the treatment of water pollution. Bi₂WO₆ tungstate is a narrow bandgap semiconductor (about 2.7eV), which can absorb part of visible light. Bi₂WO₆ is a widely used photocatalytic material for visible light response. It is widely used for photocatalytic degradation of organic dyes, drugs, heavy metals and other pollutants.

But as we all know, bismuth tungstate has six forms: nanoflake, nanosphere, nanopetal, nanobird nest, nanoparticle and nanohelix. Researchers believe that different morphologies of bismuth tungstate can be prepared by setting different parameters and conditions of hydrothermal synthesis. If it is necessary to prepare two-dimensional photocatalytic materials of bismuth tungstate with sheet structure, the following process is needed:

(1)Sodium tungstate 16.5-165 mg and cetyltrimethylamine bromide 2.5-25 mg were added to 40 mL deionized water, stirred until completely dissolved, and solution A was obtained, in which the molar ratio of sodium tungstate to cetyltrimethylamine bromide was 5:1.

(2)Bismuth nitrate pentahydrate (36.1-361 mg) was added into solution A and stirred to obtain solution B.

(3)Solution B was placed in a high-pressure reactor, sealed and then placed in a drying chamber at 120 ℃ for 24 hours. After the reaction, the product was cooled to room temperature naturally. After centrifugal separation and drying, two-dimensional bismuth tungstate nanosheets were obtained. During the synthesis process, the thickness of two-dimensional bismuth tungstate nanosheets decreased gradually with the decrease of precursor concentration, and two-dimensional bismuth tungstate nanosheets were obtained. The structure of bismuth tungstate nanosheets changes from elliptic to quadrilateral.

Two-dimensional nano-flake bismuth tungstate with controllable size and structure was synthesized by hydrothermal method. The synthesis method is simple, raw material green, low cost, short preparation period, good repeatability and easy to popularize.

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