Preparation and Tribological Behavior of N-doped Graphene Oxide Quantum Dots with MoS₂ and Al₂O₃ Nanocomposites as Lubricant Additive in Aqueous Glycerol

N-doped graphene oxide quantum dots (NGOQDs) with MoS₂ and Al₂O₃ nanocomposites were prepared by solvothermal method. The morphology and the composition and structure of the prepared composites were characterized by TEM, XRD, Raman, ATR-FTIR, and XPS. Tribological behavior of NGOQDs-MoS₂ and NGOQDs-Al₂O₃ nanocomposites as lubricant additive in aqueous glycerol were studied. Through experiments and MD simulations, the tribochemistry-induced lubrication mechanism was disclosed. The results shows that the combination of NGOQDs and hydrated glycerol can significantly improve lubrication performance, and the addition of NGOQDs-MoS₂ and NGOQDs-Al₂O₃ nanoparticles can further improve tribological properties. The formation of a tribofilm through tribochemical induced lubrication mechanism improves the wear resistance of metal surfaces.