Hydrogen fuel cells are used to convert hydrogen into electricity.
To facilitate the reaction that produces electricity, they use an expensive platinum catalyst. Scientists at Imperial College London have created a catalyst using only iron, carbon and nitrogen, which are cheap and readily available materials.
Hydrogen is the most abundant element on Earth and yet its use is hampered by high supply and storage costs. Despite being everywhere, it is almost nowhere in pure form. As such, expensive and energy-consuming methods need to be devised to extract it from various other products, such as water or natural gas. These are largely polluting processes, which nullify the role of hydrogen as a potential green fuel.
Hydrogen storage is also complicated, requiring high pressure tanks, usually made of carbon fiber materials. Burning hydrogen directly into a combustion engine is fairly straightforward, but a more efficient and cleaner way is to convert it into electricity using a fuel cell. Unfortunately, fuel cells are also very expensive to make, as they use rare materials such as platinum to facilitate the reaction that leads to the production of electricity.
An innovative technology
However, the situation is about to change dramatically as a team of researchers at Imperial College London has created a catalyst made of iron, carbon and nitrogen to replace expensive platinum components. When used wisely, they are just as effective as the precious metal in operating the combustion cell at high power.
“Currently, about 60 percent of the cost of a single fuel cell is platinum for the catalyst,” said lead researcher Anthony Kucernak of the Imperial Department of Chemistry. “In order to make fuel cells a viable real alternative to fossil fuel vehicles, for example, we need to reduce that cost.”
In order for it to work, the team produced a catalyst in which all the iron was dispersed as single atoms in an electrically conductive carbon matrix. The use of a process called transmetallation has led to radically different properties from bulk iron, acting as a good substitute for platinum. In laboratory tests, researchers showed that a single-atom iron catalyst performed similarly to platinum-based catalysts in a real fuel cell system.
The iron catalyst allows the construction of cheaper fuel cells, which will significantly reduce the cost of fuel cell applications. For now, the iron-based catalyst is not as durable as the one made of platinum, but the team is working to improve the system. Fuel cells have great potential for generating electricity not only for transportation, but also for buildings and communities.