Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite
Chua, C. K.
Webster, Richard David
Date of Issue2012
School of Physical and Mathematical Sciences
Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research.
Proceedings of the national academy of sciences
© 2012 National Academy of Sciences. This paper was published in Proceedings of the national academy of sciences and is made available as an electronic reprint (preprint) with permission of National Academy of Sciences. The paper can be found at the following official DOI: [http://dx.doi.org/10.1073/pnas.1205388109]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.