Metal-assisted mechanochemical reduction of graphene oxide

Graphene has gained much attention for a wide variety of applications including optics, electronics, and energy applications due to its unprecedented physical properties. However, a cost-effective, scalable, environmentally-benign graphene production method is crucial for realizing commercial uses of graphene in emerging applications. Reduced graphene oxide can be obtained by chemical or thermal methods, which are considered to be scalable routes for the mass production of graphene. However, these methods require toxic chemicals or high energy consumption. Here, we show that highly reduced graphene oxide can be simply synthesized from a metal-assisted mechanochemical method. Addition of magnesium during mechanical ball milling results in the selective reduction of oxygen atoms in graphene oxide. Magnesium also preferentially donates electrons necessary for restoring sp2-carbon bonds. The resulting graphene oxide is highly reduced with a high C/O ratio (∼30) and its structural characteristics in powder form are similar to those of graphite. The present metal-assisted mechanochemical method is a scalable method for facile reduction of graphene oxide because the mechanical milling method used in this study is commonly employed for many metal/ceramic products in industry.

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