Since the pioneering work on exfoliated single-layer graphene, layered inorganic nanosheet materials have been widely explored due to their unusual properties with potential applications in energy devices and optical electronics. Among these layered inorganic nanosheets, two-dimensional thin MoS₂ nanosheets show extraordinary properties such as the presence of a direct bandgap, magnetism, superconductivity and ferroelectricity. Over the past few years, solution-processed exfoliation methods of layered materials have been extensively studied; most of the exfoliation processes employ organic solvents or use surfactants as well as other functionalization agents. Although pure water is considered as an ideal solvent, however, it is generally believed stable dispersions of water could not be achieved due to poor solubility MoS₂ in water. Thus, there are very limited studies for developing of water based MoS₂ dispersions. Here we introduce a facile, green and reliable exfoliation method for producing water-dispersible MoS₂ nanosheet without surfactant. Pure water was used as a solvent and this exfoliation process was achieved by thinning the bulk MoS₂ by mechanical force between sandpapers and dispersing it through probe sonication in water. The exfoliated single or few-layered MoS₂ nanosheets were characterized by TEM and SEM images. The lateral dimensions of the nanosheets were around 500 nm to 5 µm, the same range as obtained in the organic solvents as reported. Zeta potential measurements indicated that electrical charges may be responsible for the stabilization of the dispersions. Overall, it is concluded that with this exfoliation strategy, water can be used as a useful dispersible solvent for MoS₂ nanosheets. Although the stability of the dispersions may not be as high as in organic solvents, the present method could be employed for a number of applications where the dispersions can be produced on site and organic solvents are not desirable.

自从剥离单层石墨烯的开创性工作以来，层状无机纳米片材由于其不寻常的特性而得到了广泛的探索，并潜在地应用于能源设备和光学电子领域。在这些层状无机纳米片中，二维薄MoS ₂ 纳米片表现出非凡的性能，例如直接带隙的存在，磁性，超导性和铁电性。在过去的几年中，对层状材料的固溶处理剥落方法进行了广泛的研究。大多数剥落过程使用有机溶剂或使用表面活性剂以及其他功能化剂。尽管认为纯水是理想的溶剂，但是，由于MoS ₂在水中的溶解度差，通常认为不能实现稳定的水分散。因此，对于开发水基MoS ₂分散体的研究非常有限。在这里，我们介绍一种用于生产水分散型MoS ₂的简便，绿色且可靠的剥落方法没有表面活性剂的纳米片。使用纯水作为溶剂，并且该剥离过程是通过利用砂纸之间的机械力使块状MoS ₂变稀并通过探针超声处理将其分散在水中而实现的。通过TEM和SEM图像表征剥离的单层或很少层的MoS ₂纳米片。纳米片的横向尺寸约为500 nm至5 µm，与报道的在有机溶剂中获得的范围相同。Zeta电势测量表明，电荷可能是分散体稳定的原因。总体而言，得出的结论是，采用这种剥离策略，水可以用作MoS ₂的有用的分散溶剂。纳米片。尽管分散体的稳定性可能不如在有机溶剂中那样高，但是本发明的方法可以用于许多可以在现场制备分散体并且有机溶剂是不期望的应用中。