Tungsten Disulfide/Tungsten Trioxide Monohydrate Heterojunction

Heterojunction of tungsten disulfide and tungsten trioxide monohydrate is a transverse heterojunction formed by tungsten disulfide and tungsten trioxide monohydrate with covalent bonds. It has great potential application value in the field of photocatalytic semiconductor nanocomposites.

The preparation process of tungsten disulfide/tungsten trioxide monohydrate (WS₂/WO₃ H2O) heterojunction involves the following steps:

Step One: Tungsten disulfide is stripped off with SC CO₂ to prepare monolayer or less layer tungsten disulfide.

1. 50 mg WS₂ powder is dispersed in a mixed solution of 10 mL absolute ethanol and water, and then the mixture is treated by ultrasound in ice-water bath for 2 hours.

2. At the same time, the reactor is heated to 40°C, and then the ultrasound-treated mixture is transferred and stirred.

3. Carbon dioxide is then filled into the reactor until the pressure reached 16 MPa, keeping the temperature and pressure unchanged throughout the stripping process.

4. After 3 hours of reaction in SC CO₂, carbon dioxide is discharged and the sample is collected. The suspension is dispersed in the ultrasonic machine for 3 hours and then centrifuged in the ultrasonic machine with a rotating speed of 3000 rpm for 15 minutes.

5. The centrifugation is completed and monolayer or less layer tungsten disulfide is successfully prepared.

Step Two: Heterojunction of tungsten disulfide and tungsten trioxide monohydrate is prepared by oxidation method.

1. The prepared monolayer tungsten disulfide with more active sites is easy to react with oxygen, so as to prepare tungsten trioxide monohydrate. At room temperature, tungsten trioxide and sulfuric acid are produces by the reaction of tungsten disulfide, oxygen and water. The chemical equation is as follows:

2WS₂+9O₂+4H₂O=2WO₃+4H₂SO₄

2. Less layer tungsten disulfide is inert in the reaction, so heterojunction of tungsten disulfide and tungsten trioxide monohydrate is successful prepared.

Heterojunction of tungsten disulfide and tungsten trioxide monohydrate can effectively reduce the recombination rate of photogenerated electrons-holes and prolong the lives of photogenerated carriers. The preparation process is simple. It can be carried out at room temperature.

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