Synthesis of Carboxylated-Graphenes by the Kolbe-Schmitt Process

Alex Yong Sheng Eng, Zdeněk Sofer, David Sedmidubský, Martin Pumera

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Graphene oxide is an oxidized form of graphene containing a large variety of oxygen groups. Although past models have suggested carboxylic acids to be present in significant amounts, recent evidence has shown otherwise. Toward the production of carboxyl-graphene, a synthetic method is presented herein based on the Kolbe-Schmitt process. A modified procedure of heating graphite oxide in the presence of a KOH/CaO mixture results in up to 11 atom % of carboxylic groups. The graphite oxide starting material and reaction temperature were investigated as two important factors, where a crumpled morphology of graphite oxide flakes and a lower 220 °C temperature preferentially led to greater carboxyl functionalization. Successful carboxylation caused a band gap opening of ∼2.5 eV in the smallest carboxyl-graphene particles, which also demonstrated a yellow fluorescence under UV light unseen in its counterpart produced at 500 °C. These results are in good agreement with theoretical calculations showing band gap opening and spin polarization of impurity states. This demonstrates the current synthetic process as yet another approach toward tuning the physical properties of graphene.

Original languageEnglish
Pages (from-to)1789-1797
Number of pages9
JournalACS Nano
Volume11
Issue number2
DOIs
Publication statusPublished - 2017 Feb 28

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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