Ceria/reduced Graphene Oxide Nanocomposite: Synthesis, Characterization, and Its Lubrication Application

Abstract Reduced graphene oxide nanosheet decorated with uniform ceria (CeO 2 ) nanoparticles was prepared via a simple hydrothermal method. The anchored CeO 2 nanoparticles with diameters of 3.5‐4.5 nm were well distributed on reduced graphene oxide (rGO) nanosheets. The as‐prepared CeO 2 /rGO nanocomposites can be highly dispersed into the paraffin oil to form a stable monodisperse solution at the broad temperature range from −7°C to 160°C. The tribological performance of CeO 2 /rGO nanocomposites as oil lubricant additives was systematically investigated using a MS−T3000 ball‐on‐disk tester. The results indicated that paraffin oil with 5 wt% CeO 2 /rGO exhibited the best lubrication performance in terms of the lowest friction coefficient and wear rate compared to only GO or CeO 2 nanoparticles as lubricant additives. Notably, the base oil filled with CeO 2 /rGO revealed the excellent tribological properties as friction coefficient and wear rate separately decreased by 15.85% and 76.03%, in comparison with the base paraffin oil. Moreover, optical microscope images of the wear surface of the steel disc as well showed that CeO 2 /rGO nanocomposites exhibited higher anti‐wear capability than GO nanosheet and CeO 2 nanoparticles. The unique tribological properties of CeO 2 /rGO suggested the synergistic friction reduction and anti‐wear mechanism of rGO nanosheet and CeO 2 nanoparticles.