In research published in the journal Angewandte Chemie, and featured in Nature and Chemistry World, they studied materials that have a porous sponge-like structure in which to store hydrogen — and found that bigger is not necessarily better. Bigger pores, they found, don't necessarily store the most hydrogen fuel.
The work gives a boost to attempts to cram hydrogen into a small space so that it can be used practically as a fuel. Fuel cells, which run on hydrogen and oxygen, are a potentially environmentally friendly way to power vehicles, producing only water as a waste product.
But hydrogen fuel needs to overcome a number of stumbling blocks before it can replace our oil-based economy. Not the least of these is how to safely store enough hydrogen fuel for cars to cover a reasonable distance before their supplies must be replenished.
One possible solution is to pack hydrogen into porous materials, which soak up the gas like a sponge. Professor Martin Schröder and his colleagues, Professor Neil Champness and Dr Hubberstey from the School of Chemistry, with Dr Gavin Walker from the School of Mechanical, Materials and Manufacturing Engineering at The University of Nottingham, have been investigating so-called metal organic frameworks (MOFs) — molecular scaffolding filled with tiny cylindrical pores that hydrogen gas can be forced into.
Professor Schröder said: "The idea up to this point has been to increase the pore volume, so as to fit in more gas."
That makes intuitive sense: the bigger the cylinders, the more their capacity, and the greater the inside surface area available for hydrogen to attach to. But now the painstaking University of Nottingham study has quantified the amount of hydrogen that can be put into three MOFs made of identical material but with different pore sizes. Surprisingly, the study showed that the middle-sized pores could hold the highest density of hydrogen.
Professor Schröder added: "In a very small tube, the hydrogen gas molecules all see the wall and interact with it. But in a larger tube, the molecules see less of the wall and more of each other: that interaction is weaker, so they don't pack together as closely."
The researchers conclude that there is an optimum pore size for any given material.
The US Department of Energy (DoE) has set a series of advisable targets that a hydrogen-fuelled vehicle should meet in order to be economically viable: by 2010, the storage system's capacity will need to be greater than six per cent hydrogen by weight, for example.
Schröder's team shows that their frameworks reach this requirement, and come close to the DoE's volume-density target of 45 grams per litre. In fact they have achieved the highest percentage hydrogen uptake of any such material thus far reported.
He added: "MOFs appear to be a viable alternative technology to other materials currently being investigated for hydrogen storage since they can show excellent reversible uptake-release characteristics and appropriate capacities."
Emma Thorne | alfa
Did you know how many parts of your car require infrared heat?
23.10.2017 | Heraeus Noblelight GmbH
Two intelligent vehicles are better than one
04.10.2017 | Ecole Polytechnique Fédérale de Lausanne
Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
23.10.2017 | Event News
17.10.2017 | Event News
10.10.2017 | Event News
24.10.2017 | Physics and Astronomy
24.10.2017 | Physics and Astronomy
24.10.2017 | Life Sciences