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Indexed by:Journal Papers

Date of Publication:2020-03-12

Journal:Nanotechnology

Included Journals:PubMed

ISSN No.:1361-6528

Key Words:Exfoliation,Graphene,Impinging jets,Supercritical CO2

Abstract:High quality and high quantity few-layer graphene was successfully prepared by a new impinging jets method. Natural graphite flakes were first agitated in N-Methyl Pyrrolidone with the assistance of supercritical CO2, then the half-exfoliated graphite was further stripped by the shear stress derived from the impinging jets. After the energy conversion and the stress analysis of the graphite particle during the whole exfoliation process, it revealed that the size of target mesh, the distance between the nozzle and the target, the decompression rate and the raw materials size have a significant influence on the exfoliation process. Additionally, a microscopic view of the exfoliation and dispersion mechanism of graphene in CO2-NMP was investigated by molecular dynamic simulation, CO2 was found to be beneficial for the penetration of NMP into the graphite sheets. Finally, the concentration and quality characteristics of the prepared graphene were characterized by ultraviolet-visible spectroscopy, transmission electron microscopy, raman spectroscopy and atomic force microscope. The maximum concentration was as high as 0.689mg/mL, the thickness of 68% of the product was less than 2.5nm, and the lateral dimension was from 0.5-3.0μm. These results indicated that the method was promising in large-scale industrial production.© 2020 IOP Publishing Ltd.