Scientists promise cheap graphene as carbon capture

January 28, 2020 //By
Researchers from Rice University have elaborated a simple and fast process that could potentially turn almost any carbon-based waste into large volumes of pristine graphene flakes, promising novel use cases for what could become an abundant reinforcement material for numerous compounds.

Graphene as already been proven to improve the mechanical properties of thermoplastics when blended in small quantities, increasing hardness, scratching resistance or tensile strength. Depending on the weight percentage added, it was shown to not only strengthen cement but make it conductive enough to create large-area heating resistor layers for floor heating. But today’s graphene does not come cheap, which restricts many applications where high volumes would be required.

As reported in Nature, in a paper titled “Gram-scale bottom-up flash graphene synthesis”, the so-called flash graphene is made in 10 milliseconds by heating carbon-containing materials to 3,000 Kelvin. The source material can be nearly anything with carbon content including food waste, plastic waste, petroleum coke, coal, wood clippings or biochar, and the result is what the authors describe as "turbostratic" graphene, exhibiting misaligned layers that are easy to separate, unlike A-B stacked graphene from other processes.

"With the present commercial price of graphene being $67,000 to $200,000 per ton, the prospects for this process look superb," explains Prof. James Tour, co-author of the paper.

The new process is quick and cheap, only requiring the carbon-based waste to be placed between two electrodes and zapped at 200V with a short electrical pulse. The flash process happens in a custom-designed reactor. While graphene forms, all the non-carbon elements such as oxigen and nitrogen, could also be captured as useful industrial gases.

In a flash, carbon black turns into graphene through a technique developed by Rice University scientists. From left: undergraduate intern Christina Crassas, chemist James Tour and graduate students Weiyin Chen and Duy Luong. Credit: Jeff Fitlow/Rice University

In their experiments, the researchers have converted mixed plastic waste and rubber tires into graphene, but also used coffee beens.

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