Heterostructured rGO/MoS2 nanocomposites toward enhancing lubrication function of industrial gear oils

Reduced graphene oxide (rGO)/molybdenum disulfide (MoS2) heterostructure nanosheets (rGO-MoS2-1) were synthesized via vertically growing of MoS2 on rGO skeleton using a facile one-pot hydrothermal method. Toward high-performance lubrication additive, the rGO-MoS2-1 in industrial gear oil shows extraordinary dispersity and stability because its steric hindrance effect restrains the aggregation and settling tendency. More importantly, its introduction can significantly reduce the friction (∼16.7%) and wear (up to 80%) under the sliding contact. The characterization and analysis on the worn surfaces reveal that good dispersion stability, the formation of rGO-MoS2-based lubrication protective film, and the lower shear strength induced by the inherent lattice mismatch between rGO and MoS2 are the key factors in the friction reduction and protection the tribo-interfaces against wear.