by Alison Kibe
With the availability of cost effective and easily scalable synthesis methods, researchers have begun working with porous and 3D graphene and carbon nanotube (CNT) structures. Wang, Sun, and Chen (2014) wrote a review article outline uses for foam-like structures of CNTs, graphene, and hybrids of the two. Using a process called chemical vapor deposition, it is possible to construct defect free 3D architectures. This type of method is currently used in thin film production, i.e. production of semiconductor wafers in photovoltaic cells.
What makes the porous 3D structure so useful is it’s greater surface area and structural strength. Graphene is composed of an atom thick layer of carbon rings that gives it a stable structure but means that the edges of the layer are free to interact with other atoms and molecules. The surface area of porous 3D structures means that there are more reactive edges. This is ideal for the addition of chemical functional groups, biomolecules, polymers, and other nanomaterials.
One of the major potential applications for CNT/graphene hybrids is their ability to transport ions, fuel molecules, and electrons quickly. Issues found in biofuel cells like the difficulty of electron transfers between enzymes and catalysts could be alleviated via “decorating” a 3D graphene structure with enzymatic structures.
There is a hope for graphene and carbon nanotubes as transformative super materials that will provide a variety of energy applications. But, when will we actually see any of this technology in use? In an article for the New Yorker, John Colapinto asks the question, what is graphene actually for? He points out that other technologies, like the science behind magnetic resonance imaging (MRI) technology wasn’t realized as the medical MRI machines we recognize today for nearly thirty years. In addition, in many cases graphene needs to be altered in order to be useful, but changing graphene can cancel out advantages it has over other materials. For this reason, even though graphene is known for its conductive properties, it is of little use as a semiconductor because semiconductors must be able to be turned on and off. Without changing graphene’s conductive capacity, it is impossible to turn graphene off. Perhaps we will see more commercially applicable uses for graphene and CNT in the near future, but if history is any indication, it’s a long ways off. Still, it is probably only a matter of time.
Wang, X., Sun, G., Chen, P., 2014. Three-dimensional porous architectures of carbon nanotubes and graphene sheets for energy applications. Frontiers in Energy Research 2, 1–8.
Colapinto, John. “Material Question.” The New Yorker. December 22, 2014. http://www.newyorker.com/magazine/2014/12/22/material-question