Stable dispersed N-doped carbon quantum dots-decorated 2D Ni-BDC nanocomposites towards the tribological application

Abstract

The interfacial compatibility of nanomaterials was critical for enhancing dispersibility and tribological properties in oil. In this paper, the 2D Ni-BDC nanosheets were decorated with N-doped carbon quantum dots (N-CDs) by in-situ solvothermal method, forming N-CDs/2D Ni-BDC nanocomposites constituted of ca. 9-layer nanosheet and 3 nm-size N-CDs nanoparticle. The composition and structure of N-CDs/2D Ni-BDC were revealed by a series of characterization techniques. The experiment results verified that the dispersibility of Ni-BDC/2D Ni-BDC nanocomposites was significantly improved compared with neat 2D Ni-BDC in the castor oil. In addition, we intensively investigated the tribological performance of N-CDs/2D Ni-BDC nanocomposites in the castor oil under different friction pairs. The results demonstrated that the average friction coefficient and wear scar diameter of the castor oil with 0.04 wt% N-CDs/2D Ni-BDC were reduced by 35.29% and 25% compared with 2D Ni-BDC under the ball-on-ball contact, and the average friction coefficient and wear rate were decreased by 20% and 12.3% under the ball-on-slider contact, respectively. The above results proved that the N-CDs/2D Ni-BDC nanocomposites were capable to effectively enhance the dispersibility and tribological performance in castor oil.