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An eco-friendly way to produce graphene in large quantities

An Indo-US team of researchers have developed a cleaner way of producing graphene. This research may go a long way in producing graphene in industrial scale, with minimal impact on the environment. The study was conducted by the researchers from the Indian Institute of Science and the Rice University, United States.

Graphene, a form of carbon, is an extraordinary material. It's just one-atom thick, and is millions and millions times thinner than a sheet of paper. It is hundred times stronger than steel, and also the lightest material known: a square meter of graphene weighs less than a thousandth of a gram. It lets heat and electricity to flow through it seamlessly. Of course, the applications of this wonder material are virtually limitless.

Presently, there are two ways to produce graphene on a large scale. One way is to remove oxygen from the oxide of graphite, the material from which pencil leads are made. The other technique is not straightforward: graphene tubes, called carbon nano tubes, are created first, and graphene is obtained by spreading those tubes into sheets. Yes, it is just like spreading flat a rolled sheet of paper; but the process becomes a bit too tricky when the paper is replaced by graphene. Both of these methods require the use of toxic chemicals in large quantities.

The IISc-Rice University research team has proposed a new method of producing graphene from the carbon nano tubes. They tore apart the carbon nanotubes using a specially designed machine. The whole process was carried out at a very low temperature of -123 C.The researchers also studied the process in micro-detail using state-of-the-art molecular simulations. Their results are published in the journal Carbon 89.

"Current method opens up new way of making 2D materials such as graphene at large scale without any chemicals", says Chandra Sekhar, one of the authors.

"If you hit a tube with a hammer, it fractures. If you cool the tube in liquid nitrogen and hit at high speed which is done by our machine, it fractures along particular direction and end up into a sheet", explains Chandra Sekhar. The machine called the Cryomill is designed and developed by the authors.

The purity of graphene produced by this method is close to that obtained in any other methods with the added advantage of graphene being chemical free and cheap production in large quantities.

Ever growing environmental pollution has encouraged people to look for alternatives. This breakthrough technique of producing a wonder material chemical-free opens up a new path for graphene research and its use in the industry.


About the authors:

Kamanio Chattopadhyay is a Professor at the Department of Materials Engineering, Indian Institute of Science, Bangalore. D R Mahapatra is an Associate Professor at the Department of Aerospace Engineering, IISc. B Javvaji is in the same department. C Kumar is at the Department of Materials Engineering, IISc. S Ozden and P M Ajayan are at the Department of Material Science and Nanoengineering, Rice University, United States of America. C S Tiwary is associated with the material science departments at both IISc and Rice University.




About the paper:

The paper is published in the journal Carbon 89, and can be accessed at doi:10.1016/j.carbon.2015.03.036