Solvent-driven electron trapping and mass transport in reduced graphites to access perfect graphene.

Philipp Vecera,Herwig Peterlik,Udo Mundloch,Andreas Hirsch,Frank Hauke,Konstantin F Edelthalhammer,Johannes Holzwarth

doi:10.1038/ncomms12411

Philipp Vecera, Herwig Peterlik + Show 5 more

Open Access

https://doi.org/10.1038/ncomms12411

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Abstract

Herein, we report on a significant discovery, namely, the quantitative discharging of reduced graphite forms, such as graphite intercalation compounds, graphenide dispersions and graphenides deposited on surfaces with the simple solvent benzonitrile. Because of its comparatively low reduction potential, benzonitrile is reduced during this process to the radical anion, which exhibits a red colour and serves as a reporter molecule for the quantitative determination of negative charges on the carbon sheets. Moreover, this discovery reveals a very fundamental physical–chemical phenomenon, namely a quantitative solvent reduction induced and electrostatically driven mass transport of K+ ions from the graphite intercalation compounds into the liquid. The simple treatment of dispersed graphenides suspended on silica substrates with benzonitrile leads to the clean conversion to graphene. This unprecedented procedure represents a rather mild, scalable and inexpensive method for graphene production surpassing previous wet-chemical approaches.

Highlights

We report on a significant discovery, namely, the quantitative discharging of reduced graphite forms, such as graphite intercalation compounds, graphenide dispersions and graphenides deposited on surfaces with the simple solvent benzonitrile
The fundamental finding is that the treatment of Graphite intercalation compounds (GICs) with benzonitrile (PhCN), leads to a quantitative discharging of the individual graphenide sheets upon the formation of the coloured radical anion PhCN?À, which is easy to monitor quantitatively, the accompanying exhaustive and Coulomb force-driven migration of the potassium counterions from GICs into the surrounding benzonitrile phase, the suppression of any reactions of dispersed graphenides with moisture and air that is shown to take place when no treatment with benzonitrile is provided and the successful generation of defect-free single-layer graphene suspended on silica substrates
Typical strong oxidizing agents show much higher reduction potentials, for instance tetracyanoquinodimethane with À 0.2 V versus Ag in DMF21–23. Electropositive metals such as elemental potassium can be dissolved in PhCN, which is accompanied by the formation of K þ cations and PhCN?À radical anions[24,25,26]

Summary

Introduction

We report on a significant discovery, namely, the quantitative discharging of reduced graphite forms, such as graphite intercalation compounds, graphenide dispersions and graphenides deposited on surfaces with the simple solvent benzonitrile. The fundamental finding is that the treatment of GICs with benzonitrile (PhCN), leads to a quantitative discharging of the individual graphenide sheets upon the formation of the coloured radical anion PhCN?À , which is easy to monitor quantitatively, the accompanying exhaustive and Coulomb force-driven migration of the potassium counterions from GICs into the surrounding benzonitrile phase, the suppression of any reactions of dispersed graphenides with moisture and air that is shown to take place when no treatment with benzonitrile is provided and the successful generation of defect-free single-layer graphene suspended on silica substrates This latter discovery represents a rather mild, scalable, and inexpensive method for the wet-chemical graphene production

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