Preparation of a reduced graphene oxide/zirconia nanocomposite and its application as a novel lubricant oil additive

Abstract

Nanocomposites consisting of zirconia (ZrO₂) nanoparticles and reduced graphene oxide (rGO) nanosheets were successfully fabricated by a one-pot hydrothermal method. By regulating the proportion of the precursors of the GO colloidal suspension and zirconium oxychloride (ZrOCl₂) solution, ZrO₂ nanoparticles with a diameter of about 5 nm were uniformly anchored onto the rGO nanosheets. The combination mechanism of ZrO₂ nanoparticles fully bonded onto rGO nanosheets is the formation of the monodentate or bidentate composites between the oxygen-containing groups of GO and Zr(IV) complex ions from hydrolysis of the ZrOCl₂ solution. The dispersibility and tribological properties of the prepared composites were investigated as novel lubricant additives in paraffin oil. The results suggested that the oil with a small amount of nanocomposite (0.06 wt%) exhibits good dispersibility, excellent friction-reduction and anti-wear properties as well as a high load-bearing capacity caused by the synergistic effect of the rGO nanosheets and ZrO₂ nanoparticles.