The carbon-based material, graphene, already is so versatile that it has found use in applications ranging from new types of electronic materials to 3D printing. Now, researchers in Sweden have made breakthroughs in the use of the material as part of research to find a new way to convert water and carbon dioxide into renewable energy.
Specifically, a team at Linkoping University has developed a method for producing graphene with several layers in a controlled process. It also has shown how the material acts as a superconductor in certain conditions.
The work—outlined in two new journal articles—is a big step in the direction of the team’s ultimate goal to use both energy from the sun and graphene applied to the surface of cubic silicon carbide to develop an alternative energy source.
Researchers in Sweden have used the versatile material graphene in new ways on their path to developing new sources of alternative energy. (Image source: Linkoping University)
Researchers around the world have been working to develop alternatives to fossil fuels to provide more eco-friendly forms of energy. One of the more attractive alternatives to developing these fuels is to break down water and carbon dioxide, leaving carbon, oxygen, and hydrogen as the elements left—the building blocks for fuels like ethanol and methane.
Indeed, achieving a cost-effective and efficient conversion of carbon dioxide and water to renewable fuel is the goal that the LiU researchers have to help reduce carbon dioxide emissions, said Jianwu Sun, a senior lecturer at the university, in a news release.
On their path, the LiU team already developed a method to produce a material called cubic silicon carbide, comprised of silicon and carbon but in a form that can capture energy from the sun and create charge carriers. However, it’s not sufficient alone for the development of an alternative fuel based on carbon dioxide and water, researchers said.
Turning to Graphene
That is why the team turned to graphene—one of the thinnest materials ever produced—for their latest solution. Graphene, which has high electrical conductivity among other unique properties, is composed of a single layer of carbon atoms bound to each other in a hexagonal lattice.
To control the properties of graphene for fuel-development purposes, researchers knew they had to improve the process by which it grows on a surface, which they have achieved, Sun said.
“It is relatively easy to grow one layer of graphene on silicon carbide,” he stated. "But it’s a greater challenge to grow large-area uniform graphene that consists of several layers on top of each other. We have now shown that it is possible to grow uniform graphene that consists of up to four layers in a controlled manner.”
Key to what the team developed is to solve one of the difficulties posed by multilayer graphene: The surface becomes uneven when different numbers of layers grow at different locations. Researchers want large, flat areas for their purpose. When one layer ends, however, the edge forms a tiny, nanoscale staircase.
Removing the Steps
Researchers have found a way to remove these united large steps by growing the graphene at a carefully controlled temperature, Sun said. They also have demonstrated that they can control how many layers the graphene will contain—a key first step in their ongoing research to develop fuel from water and carbon dioxide.
The LiU researchers simultaneously discovered something new about graphene while investigating the electronic properties of multilayer graphene grown on cubic silicon carbide—something they describe in an article in the journal Nano Letters. “We discovered that multilayer graphene has extremely promising electrical properties that enable the material to be used as a superconductor, a material that conducts electrical current with zero electrical resistance,” Sun explained. “This special property arises solely when the graphene layers are arranged in a special way relative to each other.”
Theoretical calculations already had predicted that multilayer graphene would have superconductive properties if the layers were arranged in a particular way. The new study shows the first experimental demonstration that this is the case, paving the way for a number of new energy-based and other applications for graphene, he said.
Some of these include the development of extremely powerful magnets found in magnet-resonance cameras—used in medical applications—as well as in particle accelerators for research. Others are to use superconducting graphene in electrical supply lines with zero energy loss as well as to build high-speed trains that float on a magnetic field.
The team also published a paper on this work in the journal Carbon.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco, and New York City. In her free time, she enjoys surfing, traveling, music, yoga, and cooking. She currently resides in a village on the southwest coast of Portugal.
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