Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hydrogen fuel for thought

01.10.2010
Rice researchers find metallacarboranes may meet DOE storage goals

New research by Rice University scientists suggests that a class of material known as metallacarborane could store hydrogen at or better than benchmarks set by the United States Department of Energy (DOE) Hydrogen Program for 2015.

The work could receive wide attention as hydrogen comes into play as a fuel of the future for cars, in fuel cells and by industry.

The new study by Rice theoretical physicist Boris Yakobson and his colleagues, which appears in the online Journal of the American Chemical Society, taps the power of transition metals scandium and titanium to hold a load of hydrogen molecules -- but not so tightly that they can't be extracted.

A matrix made of metallacarboranes would theoretically hold up to 8.8 percent of its weight in hydrogen atoms, which would at least meet and perhaps surpass DOE milestones issued a year ago for cars that would run on hydrogen fuel.

Yakobson, a professor in mechanical engineering and materials science and of chemistry at Rice, said inspiration for the new study came from the development of metallacarboranes, now well-known molecules that combine boron, carbon and metal atoms in a cage-like structure.

"A single metal atom can bind multiple hydrogen molecules," Yakobson said, "but metals also tend to aggregate. Without something to hold them, they clump into a blob and are useless."

Abhishek Singh, lead author of the study, a former postdoctoral researcher for Yakobson and now an assistant professor at the Indian Institute of Science in Bangalore, India, calculated that boron clusters would grip the titanium and scandium, which would in turn bind hydrogen. "The metals fit like a gem in a setting, so they don't aggregate," Yakobson said. Carbon would link the clusters to form a matrix called a metal organic framework (MOF), which would act like a sponge for hydrogen.

Investigation of various transition metals showed scandium and titanium to have the highest rate of adsorption (the adhesion of transient molecules -- like hydrogen -- to a surface). Both demonstrate an affinity for "Kubas" interaction, a trading of electrons that can bind atoms to one another in certain circumstances. "Kubas is a special interaction that you often see mentioned in hydrogen research, because it gives exactly the right binding strength," Yakobson said.

"If you remember basic chemistry, you know that covalent bonds are very strong. You can bind hydrogen, but you cannot take it out," he said. "And on the other extreme is weak physisorption. The molecules don't form chemical bonds. They're just exhibiting a weak attraction through the van der Waals force.

"Kubas interaction is in the middle and gives the right kind of binding so hydrogen can be stored and, if you change conditions -- heat it up a little or reduce pressure -- it can be taken out. You want the framework to be like a fuel tank."

Kubas allows for reversible storage of hydrogen in ambient conditions -- ranging from well above to well below room temperature -- and that would make metallacarborane materials highly attractive for everyday use, Yakobson said. Physisorption of hydrogen by the carbon matrix, already demonstrated, would also occur at a much lower percentage, which would be a bit of a bonus, he said.

Other studies have demonstrated how to make carborane-based MOFs. "That means they can already make three-dimensional frameworks of material that are still accessible to gas. This is very encouraging to us," Yakobson said. "There are many papers where people analyze a cluster and say, 'Oh, this will also absorb a hydrogen,' but that's not useful. One cluster is nothing.

"But if chemists can synthesize this particular framework with metallacarborane as an element, this may become a reality."

Arta Sadrzadeh, a graduate student in Yakobson's lab, is a co-author.

Read the abstract here: http://pubs.acs.org/doi/abs/10.1021/ja104544s

Artwork is available here: http://www.media.rice.edu/images/media/NEWSRELS/PR-3.jpg

David Ruth | EurekAlert!
Further information:
http://www.rice.edu

Further reports about: Hydrogen MOF chemical bond hydrogen atom hydrogen molecules

More articles from Studies and Analyses:

nachricht Amputees can learn to control a robotic arm with their minds
28.11.2017 | University of Chicago Medical Center

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>