An eco-friendly solution for liquid phase exfoliation of graphite under optimised ultrasonication conditions

Journal article

Ultrasonic assisted liquid phase exfoliation (ULPE) is a promising method for the large scale production of 2D materials. Currently, toxic solvents such as N-Methyl-2-pyrrolidone (NMP) are commonly used for the production of graphene. In this paper four solvents; three green solvents (water, ethanol and water/ethanol) plus NMP for comparison, were sonicated and examined in terms of their bubble dynamics and acoustic emissions. Advanced fundamental analysis was conducted using high-speed imaging synchronised with acoustic pressure measurements complemented by shadowgraphic photography of the emitted shockwaves, in order to determine a suitable eco-friendly solvent medium from a cavitation bubbles dynamics perspective. Thereafter, ULPE of graphite in the optimum solvent took place for 2 h under controlled ultrasonication parameters. The produced graphene samples were characterised by employing a series of techniques consisting of Ultraviolet–visible (UV–Vis) and Raman spectroscopy as well as transmission electron microscopy (TEM). A mixture of deionised water and ethanol was shown to produce a yield twice that of pure water, comprising of high quality few layer graphene (3–5 Ls) with an average area of ∼1.15 (μm)2 and stability of ∼78% for the duration of six months. This combination is a promising eco-friendly substitute for future commercial manufacturing of graphene

Authors: Morton, JA; Kaur, A; Khavari, M; Tyurnina, AV; Priyadarshi, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Carbon
• Volume: 204
• Pages: 434-446
• Publication date: 2022-12-28
• DOI: 10.1016/j.carbon.2022.12.070
• ISSN: 0008-6223
• Language: English
• Keywords: Chemical engineering; Raman spectroscopy; Optics; Nanotechnology; Exfoliation joint; Sonication; Composite material; Solvent; Graphene; Materials science; Chemistry; Graphite; Yield (engineering); Phase (matter); Organic chemistry; Environmentally friendly