But while the process of energy creation itself is sustainable, the materials used to make fuels cells are often derived from rare earth metals such as platinum. Platinum is used as a catalyst in a fuel cell because it has a porous structure, meaning it has more surface area for energy generating reactions.
Unfortunately, because these metals are often geographically specific, demand for them has caused political problems between countries. They are also expensive to harvest, making fuel cells unable to compete with the fossil fuel industry. The extraction of these resources is also environmentally problematic, since deposits of rare earth metals often occur in ecologically sensitive areas that are easily disrupted by mining processes.
Recently, scientists have found a plentiful alternative to the platinum catalyst: the carbon nanotube. A carbon nanotube is made of an atom-thick sheet of carbon, called graphene, which is rolled up into a cylinder. While scientists have tried recreating the porous quality of platinum by damaging carbon nanotubes, this process has often weakened the structures and caused them to break down. The solution was found by creating double and triple-walled nanotubes, which can handle the damage dealt to them in order to make them as porous as platinum.
Carbon is the fourth most abundant element in the world. Graphene, as an allotrope of carbon, is easily harvested and manufactured from graphite deposits (the same rock used to make pencil lead). Sustainable technology requires that energy not only be produced in a manner of a closed circuit but also that the production of the energy-creating device is just as sustainable. While research into graphene and carbon nanotubes is still new, only having been discovered in 2004 using x-ray crystallography by the University of Manchester, there have since been hundreds of scientists entering the field of carbon nanotechnology. The use of graphene in fuel cells can help bring us one step closer to the solution for sustainable energy generation. Who would have thought it was in our pencil lead all along?