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Unusual Inherent Electrochemistry of Graphene Oxides Prepared Using Permanganate Oxidants
Author(s) -
Eng Alex Yong Sheng,
Ambrosi Adriano,
Chua Chun Kiang,
Šaněk Filip,
Sofer Zdeněk,
Pumera Martin
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201301889
Subject(s) - graphene , electrochemistry , permanganate , cyclic voltammetry , oxidizing agent , chlorate , supercapacitor , materials science , inorganic chemistry , x ray photoelectron spectroscopy , chronoamperometry , graphite , oxide , chemical engineering , electrode , chemistry , nanotechnology , organic chemistry , composite material , engineering , metallurgy
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 ±1 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.