Unusual Inherent Electrochemistry of Graphene Oxides Prepared Using Permanganate Oxidants
Unusual Inherent Electrochemistry of Graphene Oxides Prepared Using Permanganate Oxidants
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DOI：
10.1002/chem.201301889
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发表时间：
2013-09-16
影响因子：
4.3
通讯作者：
Pumera, Martin
中科院分区：
文献类型：
--
作者：
Eng, Alex Yong Sheng;Ambrosi, Adriano;Pumera, Martin
石墨烯和氧化石墨烯是在电化学装置如超级电容器、电池、燃料电池和传感器中具有重要意义的材料。氧化石墨烯和还原石墨烯通常通过在强无机酸混合物中用氯酸盐（Staudenmaier，Hofmann）或高锰酸盐（Hummers，Tour）氧化剂氧化石墨来制备。在本文中，我们揭示了氧化石墨烯具有固有的电化学，即它们可以在低于典型电池电势的相对温和的电势（在+/-1V范围内）下被氧化或还原。石墨烯的这种固有的电化学性质与所使用的氧化剂有显着不同。使用氯酸盐制备的氧化石墨烯表现出化学不可逆还原，而通过基于高锰酸盐的方法制备的氧化石墨烯表现出非常不寻常的含氧基团的固有化学可逆电化学。通过循环伏安法、计时电流法和X射线光电子能谱实验深入了解了电化学行为。我们的研究结果对于电化学界具有极其重要的意义，因为它们揭示了电极材料在充电/放电循环中经历循环变化，这对储能和传感设备具有很强的影响。
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 +/- 1V) 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.