Spherical Nano Tungsten Disulfide Prepared by Hydrothermal Method

Spherical nano tungsten disulfide can be prepared by hydrothermal method using ionized water as a solvent, sodium tungstate and thiourea, along with hydroxylamine hydrochloride as reducing agent and CTAB as surfactant. It is a simple and cheap preparation method.

Hydrothermal method uses aqueous solution or mixture of water and organic matter that under high temperature and pressure as solvent, so as to dissolve those insoluble substances at ambient temperature. The solvent is in a critical or supercritical state, which increases the reaction speed. And the hydrothermal synthesis process is affected by temperature, heating rate, stirring speed and reaction time.

Spherical nano tungsten disulfide can be prepared by hydrothermal method using ionized water, sodium tungstate, thiourea, hydroxylamine hydrochloride and CTAB. The preparation process involves the following steps:

Step One: Sodium tungstate (3 mM, M: mol/L) and thiourea (10 mM) are mixed in a ratio of 3:10 at room temperature. The reducing agent hydroxylamine hydrochloride (6 mM) is dissolved in deionized water (50-60 mL) and the mixture is stirred with a magnetic stirrer until hydroxylamine hydrochloride is completely dissolved.

Step Two: The surfactant CTAB (0.2 mM) is added to the above solution and stirred until it is completely dissolved.

Step Three: Under the condition of continuous stirring, HCl (2 mol/L) is added to adjust the pH value to about 6.

Step Four: The mixed solution is transferred to hydrothermal stainless steel reactor. And then the reactor is sealed and placed in a vacuum oven. It is reacted in the equipment at 180°C for 24 hours.

Step Five: When cooled to room temperature, the prepared mixed solution is separated in a centrifuge to obtain black precipitation. The black precipitation is respectively washed with deionized water and absolute ethanol repeatedly.

Step Six: The black precipitate is dried in a vacuum oven at 80°C, and nano tungsten disulfide is obtained.

Nano tungsten disulfide prepared by hydrothermal method has high purity, good dispersibility and spherical shape. The equipment needed in this method is simple. It is a low-cost and environmentally friendly preparation method.

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