Electrochemical exfoliation of graphite in H2SO4, Li2SO4and NaClO4solutions monitored: In situ by Raman microscopy and spectroscopy
Journal article, 2021

The electrochemical exfoliation of graphite is one of the cheapest and most tunable industrial techniques to produce graphene nanosheets with a tunable degree of oxidation and solubility. Anodic oxidation allows high-yield production of electrochemically exfoliated graphene oxide (EGO) in either acid or salt solutions, with the key role played by ions electrochemically driven in between the graphene sheets. This chemical intercalation is followed by a mesoscale mechanical exfoliation process, which is key for the high yield of the process, but which is still poorly understood. In this work, we use Raman spectroscopy to simultaneously monitor the intercalation and oxidation processes taking place on the surface of highly ordered pyrolytic graphite (HOPG) during electrochemical exfoliation. The mechanism of EGO formation in either acidic (0.5 M H2SO4) or neutral (0.5 M Li2SO4) electrolytes through blistering and cracking steps is discussed and described. This process is also compared to the non-destructive intercalation of graphite in an organic electrolyte (1 M NaClO4 in acetonitrile). The results obtained show how high exfoliation yield and low defectivity can be achieved by the combination of efficient, non-destructive intercalation followed by chemical decomposition of the intercalants and gas production.

Author

Zhenyuan Xia

Chalmers, Industrial and Materials Science, Materials and manufacture

Institute for organic syntheses and photoreactivity (ISOF-CNR)

Vittorio Bellani

Universita degli studi di Pavia

Jinhua Sun

Chalmers, Industrial and Materials Science, Materials and manufacture

Vincenzo Palermo

Chalmers, Industrial and Materials Science, Materials and manufacture

Institute for organic syntheses and photoreactivity (ISOF-CNR)

Faraday Discussions

1359-6640 (ISSN) 1364-5498 (eISSN)

Vol. 227 291-305

Janus-like, Asymmetric graphene Nanosheets for Ultrafiltration and Sieving.

Swedish Research Council (VR), 2018-01-01 -- 2021-12-31.

Graphene Core Project 2 (Graphene Flagship)

European Commission (EC), 2018-04-01 -- 2020-03-31.

Subject Categories

Materials Chemistry

Other Chemical Engineering

Other Chemistry Topics

DOI

10.1039/c9fd00123a

PubMed

33346768

More information

Latest update

5/18/2021