Graphene has been used as a game-changing substance in recent years, but the way to produce the new material still needs to be improved,media New Atlas reported. Scientists at Rice University report a major breakthrough in the field – the team has demonstrated a new processing technology that can convert various junk products into “flash graphene” in a cheap and efficient way.
With its high thermal conductivity and conductivity, ultra-thin form factor and incredible strength, graphene has opened up some exciting possibilities in materials science. One of the main methods for producing single-atom-thick flakes is through chemical vapor deposition, the process by which carbon sources (usually methane) are pumped into the chamber to stimulate chemical reactions and leave graphene flakes on the surface of thin substrates.
James Tour, a chemist at Rice University, says this could be a laborious and expensive process, with graphene currently costing between $67,000 and $200,000 a tonne commercially. He led a team of researchers to develop a new way to bring together wonderful materials that could use all forms of things as carbon sources while addressing environmental waste.
The process uses so-called flash joules for heating, where current generates heat through a conductive material. Use this technique to heat any carbon-containing material to approximately 3000 Kelvin (approximately 4940 degrees F or 2730 degrees C), turning the waste into graphene flakes in about 10 milliseconds, and all remaining non-carbon elements into useful gases.
“When the process industrializes, elements such as oxygen and nitrogen that leave the flash reactor can be arrested as small molecules because of their value,” Tour said. “The most promising aspect of this new technology is the wide range of materials that can be used to generate graphene sheets. The team says that everything from banana peels to coal to other food waste, and even plastics can be used as a source of carbon and used to make graphene at a fraction of the cost of the current method.
“It’s important,” Tour says. “Between 30 and 40 percent of the world’s food is thrown away because it’s spoilt and plastic waste is getting the world’s attention. We have shown that any solid carbon-based substance, including mixed plastic waste and rubber tires, can be converted into graphene. “
Another exciting result of the study is the development of much cheaper graphene. The team has tested composites made of plastic and concrete and enhanced them with their “flash graphene”, which has proved particularly promising. The cement containing only 0.1% of the flash point, “Flash Graphene,” can reduce the huge impact of concrete production on the environment by a third, Tour said.
“By reinforcing concrete with graphene, we can reduce the amount of concrete used in buildings, thereby reducing manufacturing and transportation costs,” he says. Essentially, we are capturing greenhouse gases such as carbon dioxide and methane that may be produced by waste food in landfills. We are converting this carbon into graphene and adding it to concrete, reducing the amount of carbon dioxide produced in concrete production. Using graphene is a win-win environmental solution. “
Tour and his team hope to continue to refine their production of steamed graphene and expand it to 2.2 pounds (1 kg) of graphene per day over the next two years. Their immediate focus will be on a newly funded project to convert coal into steamed graphene. “By cheaply converting coal into more valuable building materials, it can provide a large-scale outlet for coal,” Tour said. “
The study was published in the journal Nature, and the following video outlines the technology.