Molybdenum disulfide (MoS2 ), a typical layered 2D transition metal dichalcogenide, has received colossal interest in the past few years due to its unique structural, physicochemical, optical, and biological properties. While MoS2 is mostly applied in traditional industries such as dry lubricants, intercalation agents, and negative electrode material in lithium-ion batteries, its 2D and 0D forms have led to diverse applications in sensing, catalysis, therapy, and imaging. Herein, a systematic overview of the progress that is made in the field of MoS2 research with an emphasis on its different biomedical applications is presented. This article provides a general discussion on the basic structure and property of MoS2 and gives a detailed description of its different morphologies that are synthesized so far, namely, nanosheets, nanotubes, and quantum dots along with synthesis strategies. The biomedical applications of MoS2 -based nanocomposites are also described in detail and categorically, such as in varied therapeutic and diagnostic modalities like drug delivery, gene delivery, phototherapy, combined therapy, bioimaging, theranostics, and biosensing. Finally, a brief commentary on the current challenges and limitations being faced is provided, along with a discussion of some future perspectives for the overall improvement of MoS2 -based nanocomposites as a potential nanomedicine.

2D MoS2 -Based Nanomaterials for Therapeutic, Bioimaging, and Biosensing Applications.

Porous coin-like Fe@MoS2 composite with optimized impedance matching for efficient microwave absorption

This study compares the tribological and thermophysical features of the lubricating oil using MoS2 and ZnO nano-additives. The average size of MoS2 and ZnO nanoparticles were 90 nm and 30 nm, respectively. The nanoparticles were suspended using Triton X-100 in three different concentrations (0.1, 0.4 and 0.7 wt.%) in a commercial diesel oil. Tribological properties such as mass loss of the pins, friction coefficient, and worn surface morphologies and thermophysical properties such as viscosity, viscosity index, flash point and pour point of resulting nano lubricant were evaluated and compared with those of pure diesel oil. The tribological behavior of nano lubricants was evaluated using a pin-on-disc tribometer. The worn surface morphologies were observed by scanning electron microscopy. The overall results of this experiment reveal that the addition of nano-MoS2 reduces the mass loss values of the pins in 93% due to the nano-MoS2 lubricant effect. With 0.7 wt.% in nanoparticles content, the viscosity of MoS2 and ZnO nano lubricants at 100 °C increased by about 9.58% and 10.14%, respectively. Pure oil containing 0.7 wt.% of each nanoparticle increased the flash point because of its small size and surface modifying behavior compared to the pure oil. Moreover, the addition of ZnO nanoparticles with pure oil lubricant is more suitable than MoS2 nanoparticles for improving the thermophysical properties of pure oil.

Experimental comparison between ZnO and MoS 2 nanoparticles as additives on performance of diesel oil-based nano lubricant.

Enhancing of the tribological characteristics of the lubricant oils using Ni-promoted MoS2 nanosheets as nano-additives

Electrical discharge coating using WS2 and Cu powder mixture for solid lubrication and enhanced tribological performance

Fabrication of coral-like MoS2 and its application in improving the tribological performance of liquid paraffin

MoS2 hollow microspheres used as a green lubricating additive for liquid paraffin

Friction and wear are common physical phenomena in nature, while lubrication is an effective way to decrease unnecessary friction and wear. With the rapid development of environmental protection consciousness, designing novel lubricants or lubricating additives with excellent lubricating performance and little pollution is the increasing demand of the green tribology. In this work, nanoscale coral-like molybdenum disulfide (MoS2) was prepared via a hydrothermal method. It was first used as a lubricating additive for liquid paraffin (LP), and then, it acted as a catalyst for the photoinduced degradation of waste LP after testing. Many influencing factors (modification, concentration, morphology and temperature) that can influence the tribological properties and photocatalytic degradation level were investigated. Experimental results and related analyses indicate that modification by cetyltrimethylammonium bromide (CTAB) and a proper synthesis temperature are helpful to decrease the fiction coefficient, and organic modification, bigger surface area, narrower bandgap and more rim sites with oxidation activity are advantageous to achieve better LP degradation levels. Therefore, coral-like MoS2 can serve as both lubricating additive and photocatalyst at different working stages in the full life cycle of LP, which exhibits great potential in developing environment-friendly lubricating systems.

Lei Liu

Papers

Fabrication of coral-like MoS2 and its application in improving the tribological performance of liquid paraffin

MoS2 hollow microspheres used as a green lubricating additive for liquid paraffin

Enhanced lubrication and photocatalytic degradation of liquid paraffin by coral-like MoS2