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

• Published in: Applied surface science 2022-03, Vol.579, p.152157, Article 152157
• Main Authors: Kumari, Sangita, Chouhan, Ajay, Siva Kumar Konathala, LN, Sharma, Om P., Ray, Siddharth S., Ray, Anjan, Khatri, Om P.
• Format: Article
• Language: English
• Subjects: 2D/2D Heterostructure; Dispersion stability; Friction and wear; h-BN and MoS2 nanosheets; Interfacial stacking; Surface chemistry
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.152157

[Display omitted] •Incommensurately stacked 2D/2D heterostructure of h-BN and MoS2 nanosheets (h-BN-MoS2) is synthesized by wet chemistry route.•Surface functionalization of h-BN-MoS2 heterostructure furnished excellent dispersibility.•Chemically functionalized h-BN-MoS2 heterostructure as an additive to lube oil decreased the friction (43%) and wear (96%) for steel tribopair.•Ultralow friction arises from interfaces of h-BN-MoS2 heterostructure.•Shear-induced delaminated lamellae of h-BN-MoS2 heterostructure forms a protective thin film on steel tribo interfaces.•2D/2D heterostructure can be revolutionary materials for developing new generation lubricants. 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.