Chemically functionalized 2D/2D hexagonal boron Nitride/Molybdenum disulfide heterostructure for enhancement of lubrication properties

Ultralow friction arising from interfaces of incommensurately stacked 2D/2D heterostructure of two different crystal lattices provides a promising solution for designing a new generation lubricants of superior tribological properties. Present work addressed the chemically functionalized 2D/2D heterostructure of h-BN and MoS2 nanosheets as a dispersible additive to engine oil for reducing friction and material losses. The h-BN nanosheets prepared by alkali-assisted hydrothermal exfoliation are used for growing the MoS2 lamellae via a chemical reduction in the presence of cetyltrimethylammonium bromide (CTAB). The XPS, FTIR, Raman, XRD, and HRTEM analyses confirmed the synthesis of the h-BN-MoS2-CTAB heterostructure. The grafting of CTA furnished excellent dispersibility of h-BN-MoS2-CTAB heterostructure in fully formulated engine oil, which ensured their uninterrupted supply to contact interfaces of steel tribopair. A minute dose of h-BN-MoS2-CTAB (30 ppm) to engine oil decreased the friction and wear by 44% and 96% for steel tribopair. The improved lubrication properties are ascribed to the excellent dispersibility of h-BN-MoS2-CTAB heterostructure in engine oil, low shear strength of incommensurately stacked h-BN and MoS2 lamellae, and the formation of protective thin film on steel tribo-interfaces. These findings suggest that 2D/2D heterostructure can be revolutionary materials for developing new generation lubricants.

Automated summary

This study demonstrates the use of chemically functionalized 2D heterostructure nanosheets as dispersible additives in engine oil to reduce friction and wear on steel tribopairs. The results suggest that 2D/2D heterostructures can revolutionize the development of new generation lubricants through their excellent dispersibility and low shear strength.