Kaur, Amanpreet, Morton, Justin A., Tyurnina, Anastasia V., Priyadarshi, Abhinav, Ghorbani, Morteza, Mi, Jiawei, Porfyrakis, Kyriakos ORCID: https://orcid.org/0000-0003-1364-0261, Eskin, Dmitry G. and Tzanakis, Iakovos (2024) Dual frequency ultrasonic liquid phase exfoliation method for the production of few layer graphene in green solvents. Ultrasonics Sonochemistry, 108:106954. ISSN 1350-4177 (Print), 1873-2828 (Online) (doi:10.1016/j.ultsonch.2024.106954)

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Abstract

In this work, we implement a dual frequency (24 kHz and 1174 kHz) ultrasonic assisted liquid phase exfoliation (ULPE) technique in deionized water (DIW) and other eco-friendly solvents, to produce a variety of high-quality few-layer graphene (FLG) solutions under controlled ultrasonication conditions. The resulting FLG dispersions of variable sizes (~0.2–1.5 μm2) confirmed by characterisation techniques comprising UV–Vis spectroscopy, Raman spectroscopy and high-resolution transmission electron microscopy (HR-TEM). For the first time we demonstrate that high yield of FLG flakes with minimal defects, stable for 6 +months in a solution (stability ~ 70 %), can be obtained in less than 1-hour of treatment in either water/ethanol (DIW:EtOH) or water/isopropyl alcohol (DIW: IPA) eco-friendly mixtures. We also scrutinized the underlying mechanisms of cavitation using high-speed imaging synchronized with acoustic pressure measurements. The addition of ethanol or IPA to deionized water is proposed to play a central role in exfoliation as it regulates the extend of the cavitation zone, the intensity of the ultrasonic field and, thus, the cavitation effectiveness. Our study revealed that lateral sizes of the obtained FLG depend on the choice of exfoliating media and the diameter of a sonotrode used. This variability offers flexibility in producing FLG of different sizes, applicable in a wide spectrum of size-specific applications.

Item Type:	Article
Uncontrolled Keywords:	few-layer graphene, acoustic pressure, ultrasonic exfoliation, eco-friendly solution, shock wave emission
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TP Chemical technology
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science Faculty of Engineering & Science > School of Engineering (ENG)
Last Modified:	24 Jul 2024 13:04
URI:	http://gala.gre.ac.uk/id/eprint/47631

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