We all are aware that fossil fuels are not sustainable and pollute our planet. Even though, solar and wind power are fabulous alternatives, they are limited by nature –the sun doesn’t always shine and the wind doesn’t always blow. Batteries also can store energy, but have unfortunately a low energy density. This means the relation between the weight of the device and the amount of energy stored is low. Not to forget that a battery needs to be either discarded or recharged.
A liquid fuel like petrol has a high energy density because each molecule generates a lot of energy when it is burned. Here we are on our way to find a high energy density which is also sustainable. One approach is the fuel cell.
Fuel cells use a chemical reaction to generate electricity
– continuously or just when you need it.
That means you can use it for stationary technology, for example in homes or offices and also mobile technology, like in cars or buses.
One type is the “hydrogen fuel cell” which are particularly interesting as they make electricity using hydrogen and produce just water as a by-product. Most do not require combustion, the only waste is water, this looks pretty good, doesn’t it?
Unfortunately, it’s not all good news. There are in fact, two barriers to producing fuel cells easily. The first one: you have to find hydrogen! Hydrogen is a colourless, odourless and non-toxic gas and it’s the most common element in the universe but yet it’s rarely available on Earth.
The second barrier is the price of fuel cells. To transform hydrogen into electricity you need precious and rare metals, like platinum as a catalyst. And this material does not come cheap!
Finding Iron Carbide
On their way to developing fuel cells into a viable method of generating electricity, Zoe Schnepp and her team did not stop in front of these hurdles. At Diamond these scientists are using the High Resolution Powder Diffraction beamline (I11) to explore new materials as a substitute for platinum in fuel cells.
One promising compound is called iron carbide, which is abundant, naturally occurring and cheap. Together with Diamond’s scientists, high resolution diffraction ‘fingerprints’ were obtained using the state-of-the-art instrument. They can understand what iron carbide looks like at the atomic scale and also its catalytic behaviour. To use iron carbide as a catalyst, it needs to be produced in a form that has a large surface area to volume ratio: a key characteristic of nanoparticles.
The research team found out that these nanoparticles could be made if iron carbide is combined with gelatin. Yes, the same gelatin you would use to make jelly for dessert. To form the very tiny particles of iron carbide the scientists used a furnace - a special kind of oven - mounted on the beamline and which heats the gelatin up to 700°C. Their aim is to understand exactly how this works so that they will be able to change this process to get even smaller particles to improve the efficiency of the catalysts.
This research work is still in its infancy, but the results already look intriguing. Whatever the outcome of this work, fuel cells are likely to become a much more prominent element of our energy mix in the future.