Stable Dispersed Zeolitic Imidazolate Framework/Graphene Oxide Nanocomposites in Ionic Liquids Resulting in High Lubricating Performance

The “block-on-plate” nanocomposite structure material is realized with the zeolitic imidazolate framework (ZIF-67) on graphene oxide (GO) with surface oxygen-rich functional groups. Scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractograms, fourier transform infrared spectroscopy, and ZIF-67/GO demonstrate a high capability of promoting the lubricating performance of [Choline][Proline] ([CH][P]) bio-ionic liquid. Specifically, the wear volume of the disc by [CH][P]-0.1 ZIF-67/GO is only 52% of the one lubricated by pure [CH][P]. Moreover, ZIF-67/GO shows a long time, high dispersion stability in [CH][P]. In addition, the combination of GO nanosheets and ZIF-67 can make ZIF-67/GO have better polishing effect between the steels during the friction process, which can effectively form a robust lubrication layer and improves overall lubricating properties. As a result, the interfacial lubrication can be significantly improved by these newly developed [CH][P]-ZIF-67/GO lubricants. This work offers a new promising application for ZIF-67 nanocomposites with GO in advanced lubrication systems. This work also provides a new strategy of producing lubricants containing nanoparticles with high dispersion stability, which may solve the biggest challenge in this field.