Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > New clues about a hydrogen fuel catalyst

An efficient catalyst is needed to get the half liter of hydrogen out of this small, 240 mg pellet of solid ammonia borane.
An efficient catalyst is needed to get the half liter of hydrogen out of this small, 240 mg pellet of solid ammonia borane.

Abstract:
View of rhodium-based catalyst for hydrogen-fuel system offers ideas for improvement

New clues about a hydrogen fuel catalyst

Richland, WA | Posted on August 5th, 2009

To use hydrogen as a clean energy source, some engineers want to pack hydrogen into a larger molecule, rather than compressing the gas into a tank. A gas flows easily out of a tank, but getting hydrogen out of a molecule requires a catalyst. Now, researchers reveal new details about one such catalyst. The results are a step toward designing catalysts for use in hydrogen energy applications such as fuel cells.

Scientists from the Department of Energy's Pacific Northwest National Laboratory combined experimental and theoretical studies to identify the characteristics of the catalyst, a cluster of rhodium, boron and other atoms. The catalyst chemically reacts with ammonia borane, a molecule that stores hydrogen densely, to release the hydrogen as a gas. Their results, which reveal many molecular details of this catalytic reaction, appear August 5 in the Journal of the American Chemical Society.

"These studies tell us what is the hardest part of the chemical reaction," said PNNL chemist and study author Roger Rousseau. "If we can find a way to change the hard part, that is, make it easier to release the hydrogen, then we can improve this catalyst."

Molecular Tank

Researchers and engineers are trying to create a hydrogen fuel system that stores hydrogen safely and discharges hydrogen easily, which can then be used in fuel cells or other applications.

One way to achieve such a fuel system is by "storing" hydrogen as part of a larger molecule. The molecule that contains hydrogen atoms, in this case ammonia borane, serves as a sort of structural support. The catalyst plucks the hydrogen from the ammonia borane as needed to run the device.

The PNNL chemists in the Institute for Interfacial Catalysis study a rhodium-based catalyst that performs this job fairly well, but might have potential for improvement. Their initial work showed that the catalyst worked as a molecule that contained a core of four rhodium atoms in a tetrahedron, or a triangular pyramid, with each corner decorated with boron and other elements. But the rhodium and other atoms could line up in dozens of configurations in the molecule.

That wasn't enough information for design improvements the team wanted to know which of the multitude of structures was the real catalyst, as well as how the atoms worked together to remove the hydrogen from ammonia borane. To find out, the researchers had to combine experimental work with theoretical work, because neither method was sufficient on its own.

Bustling Borane Buster

First, the team followed the catalyst-ammonia borane reaction with several technologies. One of the most important is an uncommon technique known as operando XAFS, which allowed them to take X-ray snapshots of the catalyst in action. Most researchers examine a catalyst's structure when the catalyst is at a standstill, but that is like trying to figure out how an athlete performs by watching him sleep.

Additional experiments were performed in EMSL, DOE's Environmental Molecular Sciences Laboratory on the PNNL campus. The data from the various experiments were like puzzle pieces that the team had to fit together.

To put the puzzle together, the team used computer models to construct a theoretical molecular configuration that accounted for all the data. These computationally challenging models were calculated on computers at the National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory in Berkeley, Calif.

The computer model produced a structure that best incorporated the experimental data. To test whether this structure worked properly, the team performed a computer simulation of an operando XAFS analysis of that catalytic structure reacting with ammonia borane. Then they compared the simulated data with real data gathered about the catalyst. The two sets of data matched very well, suggesting the structure they had come up with was very close to reality.

The chemical nature of the structure, along with additional experimental data, allowed the team to outline the chemical reaction occurring between the catalyst and the ammonia borane. The catalyst does not remain still, said Rousseau, making it a good catalyst but, like an active two-year old, also a difficult subject to pin down.

Plucking Atoms One at a Time

The results suggested that the active catalyst picks off hydrogen from a particular spot on the ammonia borane molecule: a nitrogen atom in the molecule holding onto two hydrogen atoms. First, the catalyst plucks one hydrogen atom off. This is the hardest part of the reaction, said Rousseau, and it makes the bond between the remaining hydrogen and boron unstable. So the molecule spits off the second hydrogen as well, and the two hydrogen atoms form molecular hydrogen, or H2 which is released as a gas and can be used in engines or fuel cells.

Additional details remain to be drawn out by the team, said Rousseau, but this study makes a big dent in what they need to know to design a good, inexpensive catalyst.

Rousseau added that the research benefitted from being based at PNNL. "An important part about this work is that we have these kinds of DOE teams where we can start with experiments and go to theory and back again. We get a lot more information this way than doing either one alone."

Reference:
Roger Rousseau, Gregory K. Schenter, John L. Fulton, John C. Linehan, Mark H. Engelhard, Thomas Autrey, Defining the Active Catalyst Structure and Reaction Pathways from Ab initio Molecular Dynamics and Operando XAFS: Dehydrogenation of Dimethylaminoborane by Rhodium Clusters, J Am Chem Soc, DOI 10.1021/ja901480u.

This work was supported by the Department of Energy's Office of Science through the Basic Energy Sciences Program.

####

About Pacific Northwest National Laboratory
Pacific Northwest National Laboratory is a Department of Energy Office of Science national laboratory where interdisciplinary teams advance science and technology and deliver solutions to America's most intractable problems in energy, national security and the environment. PNNL employs 4,250 staff, has a $918 million annual budget, and has been managed by Ohio-based Battelle since the lab's inception in 1965.

The largest non-industrial catalysis research organization in the U.S., the Institute for Interfacial Catalysis facilitates collaborative research among scientists and engineers across the Pacific Northwest National Laboratory campus and around the globe. Researchers explore a fundamental understanding of catalytic materials and the chemical reactions occurring on catalyst surfaces. This understanding is put to use in developing industrial and environmental solutions to address a secure energy future.

EMSL, the Environmental Molecular Sciences Laboratory, is a national scientific user facility sponsored by the Office of Biological and Environmental Research within the Department of Energy's Office of Science and is located at Pacific Northwest National Laboratory. EMSL offers an open, collaborative environment for scientific discovery to researchers around the world. EMSL's technical experts and suite of custom and advanced instruments are unmatched. Its integrated computational and experimental capabilities enable researchers to realize fundamental scientific insights and create new technologies.

For more information, please click here

Contacts:
Mary Beckman
(509) 375-3688

Copyright © Pacific Northwest National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Harris & Harris Group Notes Announcements by Its Portfolio Companies During the Third Quarter of 2016 September 30th, 2016

INVECAS to Enable ASIC Designs for Tomorrows Intelligent Systems on GLOBALFOUNDRIES' FDX Technology: INVECAS to Collaborate with GLOBALFOUNDRIES to Provide IP and End-to-End ASIC Design Services on 22FDX and 12FDX Technologies September 30th, 2016

How to power up graphene implants without frying cells: New analysis finds way to safely conduct heat from graphene to biological tissues September 30th, 2016

Innovation in Nanotechnology is Focus of Symposium: Annual event brings international experts to Northwestern Oct. 6 September 29th, 2016

Possible Futures

Harris & Harris Group Notes Announcements by Its Portfolio Companies During the Third Quarter of 2016 September 30th, 2016

How to power up graphene implants without frying cells: New analysis finds way to safely conduct heat from graphene to biological tissues September 30th, 2016

Nanosensors could help determine tumors ability to remodel tissue: Measuring enzyme levels could help doctors select appropriate treatments September 29th, 2016

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Announcements

Harris & Harris Group Notes Announcements by Its Portfolio Companies During the Third Quarter of 2016 September 30th, 2016

INVECAS to Enable ASIC Designs for Tomorrows Intelligent Systems on GLOBALFOUNDRIES' FDX Technology: INVECAS to Collaborate with GLOBALFOUNDRIES to Provide IP and End-to-End ASIC Design Services on 22FDX and 12FDX Technologies September 30th, 2016

How to power up graphene implants without frying cells: New analysis finds way to safely conduct heat from graphene to biological tissues September 30th, 2016

Innovation in Nanotechnology is Focus of Symposium: Annual event brings international experts to Northwestern Oct. 6 September 29th, 2016

Environment

Coffee-infused foam removes lead from contaminated water September 21st, 2016

Mathematical nanotoxicoproteomics: Quantitative characterization of effects of multi-walled carbon nanotubes: This research article by Dr. Subhash Basak et al. will be published in Current Computer-Aided Drug Design, Volume 12, 2016 September 2nd, 2016

Nanofur for oil spill cleanup: Materials researchers learn from aquatic ferns: Hairy plant leaves are highly oil-absorbing / publication in bioinspiration & biomimetics / video on absorption capacity August 25th, 2016

Researchers watch catalysts at work August 19th, 2016

Energy

Cambrios at CEATEC - Japan 2016 September 29th, 2016

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Researchers at the Catalan Institute of Nanoscience and Nanotechnology show that bending semiconductors generates electricity September 26th, 2016

Semiconducting inorganic double helix: New flexible semiconductor for electronics, solar technology and photo catalysis September 15th, 2016

Fuel Cells

Carbon-coated iron catalyst structure could lead to more-active fuel cells September 15th, 2016

Imperial College use Kleindiek micromanipulators in their research into electrochemical energy devices September 6th, 2016

Iowa State engineers treat printed graphene with lasers to enable paper electronics September 2nd, 2016

Researchers reduce expensive noble metals for fuel cell reactions August 22nd, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic