Because of the narrow band gap (about 2.80eV), special structure and high stability and other benefits, bismuth tungstate (Bi₂WO₆) is a new type of environmental friendly material, which can be as the visible light photocatalyst. Bismuth tungstate has an excellent photocatalytic activity under the visible light, and can be used for degrading organic matters, such as RhB, phenol, aldehyde, antibiotics, etc; at the same time, it can catalyze the CO₂ and water to generate fuel. The preparation methods of bismuth tungstate are solid reaction process, coprecipitation, sol-gel method, spray and hydrothermal method.

 

Compared to the normal bismuth tungstate, nanometer sheet bismuth tungstate has the larger specific surface area, higher catalytic activity and other advantages. Thus, the study of nanometer sheet bismuth tungstate is popular, and one of important researching direction is how to prepare the tiny nanometer sheet bismuth tungstate with high photocatalytic activity by the simplest operating method and the lowest energy consumption.

 

A study has manufactured nanometer sheet bismuth tungstate by solvent hot method combined with water hot method from the raw materials of ammonium metatungstate (AMT) and bismuth nitrate, the process is showed as the following living example:

1. Fetch 10mol of bismuth nitrate, 15mol of glycerin to dissolve in the 1000mol of isopropyl alcohol with stirring to get the uniform, clear solution;

2. Transfer it into the autoclave, and raise the temperature to 160°C then keep the heat preservation for 12 hours;

3. Stop heating and cool the autoclave to room temperature, then filter to get the filter cake, and then dry the filter cake at 80°C for 12 hours after the it is washed with isopropyl alcohol for 3 times, to get the glycerin bismuth powder;

4. Fetch 1mol of ammonium metatungstate to dissolve into the deionized water, and add in 13mol of glycerin bismuth powder, go on with stirring to get a uniform solution, then transfer the solution to a autoclave for heating to 180°C with thermal insulation for 24 hours after adjusting pH value to 0~1 with the nitric acid;

5. Stop heating to cool down the product to room temperature, filter the solution to get the filter cake, and then dry the filter cake under 120°C for 12 hours after it has been washed with deionized water and ethanol for 3 times, to finally get the product of nanometer sheet bismuth tungstate.