Nano Tungsten Disulfide Prepared Under High Temperature and Self-pressurization

Nano tungsten disulfide can be prepared under high temperature and self-pressurization. During the preparation process, WO3 sol, dispersant DMSO and sublimed sulfur are reacted at 900°C. And nano tungsten disulfide with different morphologies can be prepared by controlling the preparation temperature.

The preparation of nano tungsten disulfide under high temperature and self-pressure is as follows:

1. WO3 sol is prepared by sol-gel method, mixing Na2WO4 aqueous solution and cation exchange resin.

(1) 5-10g cationic resin is put into a beaker, and then 6 mol/L HCl is added into it. The mixture is stirred with glass rod to form mud. And then it is transferred into an ion exchange column. It is washed with deionized water until the effluent does not contain Cl-. Cl- is detected with 1 mol/L AgN03 solution.

(2) 10 mL 0.5 mol/L Na2WO4 solution is poured into the ion exchange column for ion exchange. And after several minutes, a transparent yellow solution can be obtained. This solution is rather unstable, and it will be polymerized into a gel within a few hours. To stabilize the gel, tungstic acid hydrate is precipitated from it and dispersant DMSO is added into it.

2. Nano tungsten disulfide is synthesized under high temperature and self-pressurization.

The 5 mL WO3 sol, 5 mL DMSO and 1 g sublimated sulfur are reacted in a self-designed reactor at 900°C under high temperature and self-pressurization. When it is cooled to room temperature, nano tungsten disulfide can be obtained.

During the preparation process, the morphology of nano tungsten disulfide is affected by the amount of DMSO and the reaction temperature. The addition of DMSO effectively disperses the precursors, which determines that nano tungsten disulfide has a flower shape.

Tungsten disulfide synthesized at 850°C may be spherical or flake. And the one synthesized at 900°C is spherical. At the optimum temperature of 900°C, tungsten disulfide with uniform size can be obtained.

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