Microwave-assisted liquid phase exfoliation of graphite fluoride into fluorographene

Fluorographene (FG), as an important class of graphene derivatives, has shown great promise in high-performance devices and lubricating materials. However, the large-scale fabrication of high-quality and impurity-free FG nanosheets still remains a main challenge. Herein, a simple liquid-phase exfoliation approach to prepare thin FG nanosheets through the preliminary intercalation of raw graphite fluoride (GrF) particles by N,N-dimethyl formamide molecules, followed by a short-time microwave treatment is reported. Atom force microscopy measurements demonstrate that as-prepared FG nanosheets are comprised of no more than four monolayers after the microwave irradiation. After exfoliation, a small amount of aromatic C=C groups in the FG nanosheets are restored, which slightly lowers the F content in FG as compared with the raw GrF. Besides, no other side reaction and impurity elements are introduced during the exfoliation process as revealed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The resultant high-quality FG nanosheets exhibit excellent thermal stability and remarkable lubrication behavior in oil, and thus can be used as a new class of graphene derivatives with the capability of large-scale fabrication for the future device and various other applications.