▎ 摘　　要

In this work, we investigated the effect of oxidation treatment on tribological properties of multilayered graphene using a combination of different characterization techniques and molecular dynamics (MD) simulation. The sliding friction of graphene and oxidized graphene (GO-1 h, GO-3 h and GO-6 h) were examined by conducting ball-on-disk tests. Tribological studies show that the friction coefficient (COF) and run-in period of graphene increase with the degree of oxidation, but its wear life tends to increase first and then decrease, and GO-1 h has the best value. The MD simulation results corroborate these observations and further reveal the reasons for these changes by studying the morphology, diffusion rate, interlayer distance, carbon skeleton and sliding distance of graphene and GO sheets during friction. The research mainly includes three aspects: 1. the effect mechanism of grafted oxygen atoms on the structure, COF and wear life of graphene; 2. the microstructure changes of graphene and GO flakes under different loads; 3. the influence of each oxygen-containing functional group on the tribological properties of graphene. Thus, our study provides a better understanding of the lubrication and failure mechanisms of graphene and GO and proposes optimized graphene structure with better tribological performances.