Graphene is a compound composed of a single layer of carbon atoms linked together in a hexagonal pattern. Graphene is both extremely light and strong, and can conduct electricity, which makes it an exciting material for research in a variety of applications, such as aerospace and mobile devices. Unfortunately, it is very challenging to produce quickly and in bulk. Currently, the best way to produce graphene is to take graphite, the kind you might use in a pencil, remove a layer with regular office tape, and then separate off the single layer graphene sheets. However, this is slow and expensive. Other methods, such as depositing vapor from a gas to form graphene or using chemical treatments of graphite, can be more efficient, but they tend to produce more impurities in the resulting graphene.
Recently, researchers from the Indian Institute of Technology Patna developed a way to produce graphene using a plasma gun that they hope is scalable while still producing high quality material. Plasma guns take gas-phase ions, which are charged particles, and spray them at a surface. In the case of graphene, when the ions hit the surface at a high temperature, single layers of graphene are separated from the 3-D graphite structure. A centrifuge, which spins samples quickly to separate them based on density, can then be used to separate the remaining graphite from the graphene produced and ensure high purity. This method is attractive because it can produce single-layer graphene 85% of the time without dangerous chemicals or expensive solvents.
The researchers estimate that the plasma gun method costs about $1.12 per gram of graphene. Right now, at the lab scale, this method can produce 48 grams of graphene in one hour, but researchers hope to be able to scale that up to produce more of the compound in the future.
The first author Aminul Islam works in Department of Metallurgical and Materials Engineering, Indian Institute of Technology Patna and focuses on plasma sprayed coatings.
Managing Correspondent: Emily Kerr
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Image Credit: LaurensvanLieshout Plasma spray process