Tungsten Disulfide Nanoparticles

In recent years, the research of two-dimensional layered materials has attracted the attention of scientists, especially the rapidly developing graphene nanomaterials, which have the characteristics of high strength, excellent conductivity and thermal conductivity, and are widely used in the field of sensors. Graphene is known as the king of new materials. However, graphene is a two-dimensional material with zero band gap and can not be used as channel layer of transistors, which limits its further application in nano-electronic devices and photoelectric conversion.

Two-dimensional transition metal materials also have graphene-like structure, and exhibit excellent physical and chemical properties in the fields of optics, electricity and sensors. Especially transition metal chalcogenides, especially W VI transition metal sulfides - tungsten disulfide.

The single-layer nanometer tungsten disulfide material has a two-dimensional ordered layered structure and unique physical and chemical functional properties, and its structure is similar to graphene. The transition metal chalcogenide passes through the strong inner layer covalent MS bond, and the weak van der Waals force layers interact with each other. The role is combined. Its anisotropic layered structure has excellent optical, electronic and mechanical properties, and has high specific surface area, surface effect, quantum size effect and small size effect. It is widely used in electrical materials, nano-sensors, nano-catalytic materials. , nano-lubricating materials and other fields, is one of the hot new functional materials for foreign research in recent years.

Nano tungsten disulfide can not be directly obtained by natural ore processing. Due to its unique two-dimensional nano material layered structure, the development of high-efficiency, environmentally friendly and economical nano-tungsten disulfide new functional materials has become a research hotspot. At present, the mainstream preparation scheme of nanometer tungsten disulfide has mechanical stripping method, hydrothermal method, chemical vapor deposition method, sol-gel method, in-situ surface modification method, etc. In general, various methods are insufficient, nanometer The production cost of tungsten disulfide is relatively high.

1.In the field of biomedical materials: Tungsten disulfide can be used as a medical contrast agent in photothermal treatment from now to the future. This is because tungsten disulfide is a layered two-dimensional material with a hexagonal system due to its strong absorption in the near infrared (NIR) region and better biocompatibility. Recently, researchers have developed multi-functional nano-sized tungsten disulfide two-dimensional materials by tracking WS₂ to evaluate their positioning in cell and tissue environments. Combined with medical diagnosis, imaging and treatment, they are widely used in the detection and analysis of biomedical fields. Cancer treatment, toxicology, cell imaging, antibacterial and many other aspects.

2. In the field of mechanical lubricating materials, tungsten disulfide is a two-dimensional layered material with hexagonal crystalline system. In WS₂ layer, W and S are bonded by strong covalent bonds, while in the interlayer, S-S molecular bonds are bonded by weak van der Waals force. The interaction force between layers is weak and bond energy is low. It is easy to displace during friction process, so it has low friction coefficient. In addition, nano-tungsten disulfide can adsorb and fill the uneven surface of the material in time, and play a certain self-repairing role. Transition metal nano-tungsten disulfide can maintain excellent lubrication performance in the range of -273-425 ℃. It is obviously superior to traditional lubricants. It can adapt to various harsh conditions such as high temperature, high pressure, high vacuum, high load, high speed, high radiation, strong corrosion and ultra-low temperature. It is widely used in military, aerospace, satellite, aerospace and other high-tech fields. Molybdenum disulfide has similar properties, but it is inferior to molybdenum disulfide in comparison with molybdenum disulfide.

3.In the field of catalysis, tungsten disulfide is an indirect semiconductor with large specific surface area. Like tungsten oxide materials, it can also be used as a photocatalyst. It can absorb energy under visible light irradiation, generate electron E and hole h by transition, and react with water to form hydroxyl radicals with high reactivity and strong oxidation. In order to degrade large molecules of organic dyes or organic matter into small organic molecules and inorganic ions. Photocatalysts (photocatalysts) are the main means to control environmental pollution in the future, and their prospects are worth looking forward to.

In addition, tungsten disulfide, like other types of tungsten heteropoly acid catalysts, can also be used in petrochemical industry. It has the characteristics of high cracking performance, stable catalytic activity, long service life, low toxicity, good thermal stability and chemical stability. It can be used as an effective hydrotreating catalyst for oilfield hydrocracking and hydrodesulfurization.

4.In the field of optoelectronics, tungsten disulfide is a bipolar semiconductor with unique characteristics of n-type and p-type semiconductors. Layered tungsten disulfide has two-dimensional layered crystal structure, strong covalent bonds in the inner plane, and weak van der Waals force-dominated external plane interactions, which make high-quality heterojunctions possible. At the same time, the heterojunction formed by stacking graphene as a special two-dimensional material with layered WS₂ also shows unique physical properties, which attracts the attention of researchers and greatly promotes the development of layered tungsten disulfide in the fields of micro (nano) optoelectronics, electronic devices, photovoltaic industry and transistors. For example, researchers have applied tungsten disulfide to Q-switched erbium-doped pulse lasers and transistors.

5. Tungsten disulfide is one of the most anticipated materials in the field of new energy. Tungsten disulfide is similar to graphene in structure and has the advantages of high specific capacity and high specific surface area. Tungsten disulfide has a layered structure connected by weak van der Waals force, and its size is generally nano-scale. There will be hollow interior and gap between layers. The space proportion will be large, which can be used for effective hydrogen storage and lithium storage. At the same time, its thermal stability is good, the material can be used repeatedly and charge and discharge in the loop. It is an excellent energy storage battery material, so it can be widely used in solar cells, fuel cell anodes, lithium battery anodes, supercapacitors and other aspects. For example, the two tungsten sulphide supercapacitors have been reported by scientists in the United States on the China Tungsten line.

Nano tungsten disulfide seems to be omnipotent, but researchers also believe that the most important applications and research of nano-tungsten disulfide in the future will focus on medical, photoelectric and new energy fields, because the application of tungsten disulfide is not irreplaceable, whether it is lubrication or catalyst. On the contrary, owing to the cost factors of tungsten disulfide at the present stage, it must be in the high-end field to reflect its due value, which is also the future development focus of single-layer nano-tungsten disulfide. (Part of the article is excerpted from "Application of Tungsten Disulfide Nanomaterials" by China Tungsten Industry.

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