Materials for Hydrogen Storage by Ethan Martin

Fossil fuels are an increasing problem for the world with scientists everywhere researching how to make efficient and renewable fuel sources. One of these developments is hydrogen cars, which store hydrogen in tanks and turn it into an electric current with water as a by-product. A problem with this is that high pressures are needed, which is dangerous for the driver. How could this problem be fixed?

That’s what I was looking at in my in2scienceUK placement. I was looking at a special material called a MOF, which is a Metal Organic Framework. At an atomic level they have pores in them, meaning they have the ability to adsorb a vast amount of hydrogen. This is useful in hydrogen cars and they are able to store hydrogen very densely and at a lower, safe pressure.

The MOF I was making is called IRMOF-1. I started by weighing out zinc nitrate hexahydrate and terephthalic acid, after which I combined it in a Teflon liner with diethyl formamide. This is when I got to see more advanced scientific equipment: a magnetic stirrer, which uses a rotating magnetic field to cause the stir bar to spin. After it had been stirred it was heated at 105°C overnight in an oven. The next day when it was taken out a few crystals had formed in the bottom, not as much as expected but not every experiment can go perfectly and it was more than enough. The sample was then vacuum filtered until it was completely dry and 0.0718g of my MOF had been synthesised.

Ethan Martin fig 1

The next thing we needed to find was the surface area, using a BET Surface Area Analyzer. This machine puts gas into the tubes, the gas we used being nitrogen gas, and as the MOF adsorbs the gas and makes it more dense in the material the overall pressure changes. It measures the pressure and uses this measurement to find out how much nitrogen gas was adsorbed by the material.

Ethan Martin fig 2

Using the BET equation with the values from the machine I was able to deduce the surface area of my MOF, which was 1149m² per gram, roughly the area of half an Olympic swimming pool in something the size of a button!  Although the recommended surface area for practical use is 3000m² per gram, it is still a lot and astonishing how something that small can have a surface area that big.

The week overall was very interesting and I was able to see the research process behind technology we use today, as well as being able to use equipment I never I would of used before. The placement was worth it and the information I’ve received will really benefit me. I’m glad I managed to be part of such an amazing experience!

Ethan undertook his in2scienceUK placement at the University of Bath