Unusual Inherent Electrochemistry of Graphene Oxides Prepared Using Permanganate Oxidants. Issue 38 (9th August 2013)

• Record Type: Journal Article
• Authors: Eng, Alex Yong Sheng; Ambrosi, Adriano; Chua, Chun Kiang; Šaněk, Filip; Sofer, Zdeněk; Pumera, Martin
• Is Part Of: Chemistry. Volume 19:Issue 38(2013)
• Page Start: 12673
• Page End: 12683
• Publication Date: 2013-08-09
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201301889
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>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 <italic>chemically irreversible</italic> reductions, whereas graphene oxides prepared through permanganate‐based methods exhibit very unusual inherent <italic>chemically reversible</italic> 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.</p> </abstract>