Hydrogen-powered vehicles emit only water vapor from their tailpipes, offering a cleaner alternative to fossil-fuel-based transportation. But for hydrogen cars to become mainstream, scientists need to develop more efficient hydrogen-storage systems.

Now, researchers reporting in ACS' Chemistry of Materials have used metal-organic frameworks (MOFs) to set a new record for hydrogen storage capacity under normal operating conditions.

According to the U.S. Department of Energy, in 2017 the U.S. had 34 publicly accessible hydrogen fueling stations, with 31 of these in California. Along with increased fueling infrastructure, technological advances are needed for the widespread adoption of hydrogen cars. In particular, improved hydrogen storage systems could increase the driving range of the automobiles while reducing cost.

Current hydrogen cars use expensive, bulky cooling or compression systems to store enough hydrogen for acceptable driving ranges. Jeffrey Long and colleagues wondered if they could use MOFs to store more hydrogen fuel under normal driving conditions.

MOFs are compounds that contain metal ions coordinated to organic ligands. The 3D structures of some MOFs form pores that strongly adsorb molecules of hydrogen gas and cause them to attract other molecules, which could allow the gas to condense under near-ambient conditions.

To determine the best MOF for hydrogen storage, the researchers tested four different compounds - two that contained nickel and two that contained cobalt as the coordinating metal. A MOF called Ni2(m-dobdc) showed the highest hydrogen-storage capacity over a range of pressures and temperatures.

At ambient temperature and a much lower tank pressure than used in current hydrogen vehicles, Ni2(m-dobdc) set a new record for hydrogen storage capacity of 11.9 g of fuel per liter of MOF crystal.

The MOF had a significantly greater storage capacity than compressed hydrogen gas under the same conditions. When the researchers examined the structure of the MOF by neutron diffraction, they found that a single pore contained seven specific binding sites for hydrogen gas that enabled dense packing of the fuel.

The abstract that accompanies this study is available here

Related Links
American Chemical Society
Bio Fuel Technology and Application News

Tweet

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

Scientists uncovered the mechanism of fungal luminescence and created luminescent yeasts
Moscow, Russia (SPX) Nov 27, 2018
Russian scientists together with colleagues from UK, Spain, Brazil, Japan and Austria have fully described the mechanism of fungal luminescence. They found that fungi utilize only four key enzymes to produce light and that transfer of these enzymes into other organisms makes them bioluminescent. Some living organisms can glow due to special chemical reactions taking place in their bodies. Such organisms are called bioluminescent; they include fireflies, jellyfish and worms, among others. They use ... read more