Microwave- and Nitronium Ion-Enabled Rapid and Direct Production of Highly Conductive Low-Oxygen Graphene

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• 作者：Pui Lam Chiu ; Daniel D. T. Mastrogiovanni ; Dongguang Wei ; Cassandre Louis ; Min Jeong ; Guo Yu ; Peter Saad ; Carol R. Flach ; Richard Mendelsohn ; Eric Garfunkel ; Huixin He
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：April 4, 2012
• 年：2012
• 卷：134
• 期：13
• 页码：5850-5856
• 全文大小：451K
• 年卷期：v.134,no.13(April 4, 2012)
• ISSN：1520-5126

文摘

Currently the preferred method for large-scale production of solution-processable graphene is via a nonconductive graphene oxide (GO) pathway, which uncontrollably cuts sheets into small pieces and/or introduces nanometer-sized holes in the basal plane. These structural changes significantly decrease some of graphene鈥檚 remarkable electrical and mechanical properties. Here, we report an unprecedented fast and scalable approach to avoid these problems and directly produce large, highly conductive graphene sheets. This approach intentionally excludes KMnO₄ from Hummers鈥?methods and exploits aromatic oxidation by nitronium ions combined with the unique properties of microwave heating. This combination promotes rapid and simultaneous oxidation of multiple non-neighboring carbon atoms across an entire graphene sheet, thereby producing only a minimum concentration of oxygen moieties sufficient to enable the separation of graphene sheets. Thus, separated graphene sheets, which are referred to as microwave-enabled low-oxygen graphene, are thermally stable and highly conductive without requiring further reduction. Even in the absence of polymeric or surfactant stabilizers, concentrated dispersions of graphene with clean and well-separated graphene sheets can be obtained in both aqueous and organic solvents. This rapid and scalable approach produces high-quality graphene sheets of low oxygen content, enabling a broad spectrum of applications via low-cost solution processing.