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
Improvement of the operating range and increasing of the reliability of integrated circuits
09.11.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH
New algorithm for optimized stability of planar-rod objects
11.08.2016 | Institute of Science and Technology Austria
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy