Tyurnina, A. V., Morton, J. A., Kaur, A., Mi, J., Grobert, N., Porfyrakis, Kyriakos ORCID: 0000-0003-1364-0261, Tzanakis, I. and Eskin, D. G. (2023) Effects of green solvents and surfactants on the characteristics of few-layer graphene produced by dual-frequency ultrasonic liquid phase exfoliation technique. Carbon, 206. pp. 7-15. ISSN 0008-6223 (doi:https://doi.org/10.1016/j.carbon.2023.01.062)

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Abstract

Nowadays, one of the promising methods for scalable graphene production is ultrasound-aided liquid phase exfoliation (ULPE) of graphite. Two current limiting factors of ULPE are the use of harmful solutions (such as N-Methyl-2-pyrrolidone or Dimethylformamide) and a relatively low graphene yield. In this study, we demonstrate a new dual frequency (20 kHz and 1174 kHz) ULPE approach in various eco-friendly media, which enabled us to produce various few-layer graphene (FLG) solutions of high quality. By implementing sophisticated characterisation techniques consisting of Raman spectroscopy, UV–vis spectroscopy and high-resolution electron microscopy, the final graphene flakes structure was confirmed to correlate the properties of each individual solution. The thinner (∼3 layers) and larger (∼1.5 μm2) flakes were observed while using just water, with the highest yield (11%) of smaller FLG flakes to be achieved in the mixture of water and a surfactant. In order to understand the cavitation mechanism in different solutions, the ULPE process was investigated by acoustic measurements. This study demonstrates the crucial role of ethanol (as a solvent) and surfactants as it regulates the cavitation power and intensity of the ultrasonic field and, thereby, the cavitation effectiveness. It is suggested that the mixture of water, ethanol and a surfactant is the best medium for ULPE process where a high yield of low-defective FLG flakes can be obtained in a solution stable at least for 3 months (around 80%).

Item Type:	Article
Uncontrolled Keywords:	graphene; acoustic pressure; ultrasonic exfoliation; eco-friendly solution; shock wave emission
Subjects:	Q Science > Q Science (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:	28 Feb 2023 16:10
URI:	http://gala.gre.ac.uk/id/eprint/38710

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