Facile construction of graphene oxide/CeO2 nanohybrid for enhancing tribological properties of green rapeseed oil

The ultra-small size and long-term dispersion stability of nanomaterials are the key factors affecting the anti friction and wear-resistant effect on lubricating oil. In this study, the CeO2 nanoparticles with size of about 8.1 nm were in-situ anchored on the surface of graphene oxide (GO) nanosheets to obtain GO/CeO2 nanohybrid through a facile solvothermal method. The microstructure and chemical composition of the GO/CeO2 were characterized by FESEM, HRTEM, XRD, and XPS. The as-prepared GO/CeO2 could keep outstanding dispersion in rapeseed oil for 60 days, suggesting the ultra-small CeO2 decorating GO had long-term dispersion stability in rapeseed oil. Moreover, the effect of GO/CeO2 on the lubricating behaviors of rapeseed oil were explored using a ball-on-disc friction tester. Results showed that the GO/CeO2 nanohybrid decreased the average coefficient of friction and wear rate of rapeseed oil more significantly than single GO or CeO2 nanoparticles. At the addition of 0.1 wt% GO/CeO2, the friction coefficient of rapeseed oil decreased by 36.5 % and wear rate decreased by 62.4%. In addition, the lubricating mechanisms of GO/CeO2 nanohybrid in rapeseed oil were proposed. This study could provide a novel strategy for the construction of ultra-small CeO2 nanoparticles and promote the develop high-performance green lubricant additive of GO/CeO2 nanohybrid.