RICE (US) — You can make graphene out of almost anything. Even Girl Scout cookies. And talk about profit—at $250 for a two-inch square, a box of shortbread cookies could earn $15 billion.
In a paper published in the journal ACS Nano, scientists described how graphene—a single-atom-thick sheet of the same material in pencil lead—can be made from just about any carbon source, including food, insects, and waste.
“I said we could grow it from any carbon source—for example, a Girl Scout cookie, because Girl Scout cookies were being served at the time,” says James Tour, professor of mechanical engineering and materials science and of computer science at Rice University. “So one of the people in the room said, ‘Yes, please do it. … Let’s see that happen.'”
A sheet of graphene made from one box of shortbread cookies would cover nearly three football fields.
The scientists say the experiment is a whimsical way to make a serious point: that graphene—touted as a miracle material for its toughness and conductivity since its discovery in 2004—can be drawn from many sources.
Tour and graduate students Gedeng Ruan, lead author of the paper, and Zhengzong Sun, also tested other materials, including chocolate, grass, polystyrene plastic, insects (a cockroach leg) and even dog feces.
In every case, the researchers were able to make high-quality graphene via carbon deposition on copper foil. In this process, the graphene forms on the opposite side of the foil as solid carbon sources decompose; the other residues are left on the original side. Typically, this happens in about 15 minutes in a furnace flowing with argon and hydrogen gas and turned up to 1,050 degrees Celsius.
Tour expects the cost of graphene to drop quickly as commercial interests develop methods to manufacture it in bulk. In earlier research, Tour described a long-sought way to make graphene-based transparent electrodes by combining graphene with a fine aluminum mesh. The material could possibly replace expensive indium tin oxide as a basic element in flat-panel and touch-screen displays, solar cells, and LED lighting.
The new findings have “a lot to do with current research topics in academia and in industry,” Tour says. “Carbon—or any element—in one form can be inexpensive and in another form can be very expensive.”
Diamonds are a good example., he says. “You could probably get a very large diamond out of a box of Girl Scout cookies.”
Sandia National Laboratory, the Air Force Office of Scientific Research, and the Office of Naval Research MURI program funded the research.
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