Abstract
The search for graphene or few-layer graphene production methods that are simple, allow mass production, and yield good quality material continues to provoke intense investigation. The present work contributes to this investigation through the study of the aqueous exfoliation of four types of graphene sources, which are namely graphite and graphite nanoflakes with different morphologies and geographical origins. The exfoliation was achieved in an aqueous solution of a soluble pyrene derivative that was synthesized to achieve maximum interaction with the graphene surface at low concentration (5 × 10−5 M). The yield of bilayer and few-layer graphene obtained was quantified by Raman spectroscopic analysis, and the adsorption of the pyrene derivative on the graphene surface was studied by thermogravimetric analysis and X-ray diffraction. The whole procedure was rationalized with the help of molecular modeling.
Highlights
Graphene has emerged as an exciting material that has been intensively studied throughout the last decade, revealing potential applications in various fields [1,2,3]
The analysis demonstrated the extent of exfoliation into the bilayer graphene of 16%, 23%, and 12% for Graphexel, Micrograf, and GnPH5, respectively
A pyrene derivative was synthetized through a simple and low-cost functionalization methAodoplyorgeynethadterleivaadtsivteo awhaisghsyynitehldetiozfedthethfirnoaulgchomaposiumnpdl,eanadndcalnowpo-cteonsttiaflulyncbtieonscaalilzeadtiuopn fmoretlhaorgdeo-lsocgaylethparot dleuacdtsiotno. aThhiegshoyluieblidlitoyf othfethfiins aplycroemnepdouernidv,atainvde icnanwpaoteternatlilaolwlyebdeitsscaulseedfuopr tfhoer large-scale production. The solubility of this pyrene derivative in water allowed its use for the exfoliation and stabilization of different types of graphite in aqueous media
Summary
Graphene has emerged as an exciting material that has been intensively studied throughout the last decade, revealing potential applications in various fields [1,2,3]. The extrapolation of its outstanding properties observed on the lab-scale into large-scale industrial applications is limited by the lack of effective methods for the large scale production of good quality graphene. The liquid phase exfoliation (LPE) of graphite is a potentially viable cost-effective process that can be upscaled to the mass production of graphene and few layer graphene (FLG). Water is a “green” solvent, and its use in this process is a step to overcome this problem. It has a high surface tension (72 mJ m−2), which limits its interaction with graphite and graphene, and the ability to form stable suspensions. Solvents with surface tensions of near 40 mJ m−2 [4] are reported to be ideal for the exfoliation of graphite into graphene [5]
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