PEG-assisted solvothermal synthesis of MoS2 nanosheets with enhanced tribological property

Molybdenum disulfide (MoS2) nanoparticles are widely used as oil additives for obtaining low friction and wear. In this article, MoS2 nanosheets with ultrathin shape and structure defects were prepared by a facile solvothermal method with the aid of polyethylene glycol (PEG 200). The products were analysed by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR). Results indicated that PEG 200 played a crucial role as the shape controller in the formation of different MoS2 structures. Interestingly, the prepared MoS2 perform excellent in improving the friction-reducing and antiwear properties of oils. More importantly, the lubricating behaviour of the obtained MoS2 nanosheets as oil additives was still effective in the harsh condition of heavy load and high temperature. Further, the excellent lubrication performance of the prepared MoS2 was discussed based on the exfoliation into individually ultrathin nanosheets and nanosized debris, and the formation of MoS2-based tribofilm inside the wear tracks.