Unusual inherent electrochemistry of graphene oxides prepared using permanganate oxidants

Alex Yong Sheng Eng, Adriano Ambrosi, Chun Kiang Chua, Filip Šaněk, Zdeněk Sofer, Martin Pumera

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

Graphene and graphene oxides are materials of significant interest in electrochemical devices such as supercapacitors, batteries, fuel cells, and sensors. Graphene oxides and reduced graphenes are typically prepared by oxidizing graphite in strong mineral acid mixtures with chlorate (Staudenmaier, Hofmann) or permanganate (Hummers, Tour) oxidants. Herein, we reveal that graphene oxides pose inherent electrochemistry, that is, they can be oxidized or reduced at relatively mild potentials (within the range ±1a V) that are lower than typical battery potentials. This inherent electrochemistry of graphene differs dramatically from that of the used oxidants. Graphene oxides prepared using chlorate exhibit chemically irreversible reductions, whereas graphene oxides prepared through permanganate-based methods exhibit very unusual inherent chemically reversible electrochemistry of oxygen-containing groups. Insight into the electrochemical behaviour was obtained through cyclic voltammetry, chronoamperometry, and X-ray photoelectron spectroscopy experiments. Our findings are of extreme importance for the electrochemistry community as they reveal that electrode materials undergo cyclic changes in charge/discharge cycles, which has strong implications for energy-storage and sensing devices. Electrochemical devices: Graphene oxides prepared with different oxidants show distinct electrochemistry; those prepared using chlorate exhibit chemically irreversible reductions, whereas graphene oxides prepared through permanganate-based methods exhibit very unusual inherent chemically reversible electrochemistry of their oxygen-containing groups (see figure). These findings have strong implications for energy-storage and sensing devices.

Original languageEnglish
Pages (from-to)12673-12683
Number of pages11
JournalChemistry - A European Journal
Volume19
Issue number38
DOIs
Publication statusPublished - 2013 Sep 16

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

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