Facile one pot pyrolysis synthesis of carbon quantum dots and graphene oxide nanomaterials: All carbon hybrids as eco-environmental lubricants for low friction and remarkable wear-resistance

All carbon hybrids containing carbon quantum dots (CQDs) and graphene oxide (GO) have been prepared via one pot pyrolysis of citric acid (TDCA). Their relationships between microstructures, compositions and tribological peformance have been investigated. The TDCA as lubricants in PEG synthetic lube base oil exhibited remarkable friction-reducing in boundary lubrication. Importantly, the anti-wear enhanced significantly with increased loads, while the friction-reduction performance increased slightly. The excellent tribological performance is due to the synergistic effect of sphere-like CQDs and GOs absorbed on the sliding surface, Moreover, the high load induced more TDCA deposited on interface and the carbons inclined to degrade and generate more ordered structure, which protected interface better against undesirable friction and wear.