April 7, 2009

MEDIA CONTACT: Nick Massella
202-994-3087; massella@gwu.edu

***SCIENCE AND TECHNOLOGY EDITORS, REPORTERS AND PRODUCERS***
***Conference Call Open to Media Only***

GW RESEARCHERS DEVELOP NEW X-RAY TECHNIQUE TO STUDY FUEL CELL OPERATIONS
APRIL 15, 2009

EVENT:

How can we extend the longevity of fuel cells? Dr. David Ramaker and his research group at The George Washington University have developed a new technique called Delta X-ray Absorption Near Edge Structure (? XANES). The new technique provides information that enables us to understand why some catalysts in fuel cells work better than others, why some get poisoned more than others, and why some age (deteriorate) more than others. Many problems still exist with modern day fuel cells, but this research and other techniques are shedding light on new catalysts that hopefully will alleviate these problems. Dr. Ramaker will explain how we may be able to improve the performance of fuel cells and answer any questions.

WHEN:

Wednesday, April 15, 2009; 2 p.m.

RSVP:

This information session is exclusively for members of the media. To RSVP, contact Nick Massella at 202-994-3087 or massella@gwu.edu.

BACKGROUND:

X-ray Absorption Spectroscopy (XAS) measures the amount of light that is absorbed by the studied sample such as metal catalysts (the absorption coefficient). An intense x-ray beam, such as that coming from a synchrotron (a large ring with electrons circulating at high speeds), is needed to take XAS. The Extended X-ray Absorption Fine Structure (EXAFS) in the absorption coefficient can provide structural information about the sample utilizing a procedure developed over the last 25 years. The new ? XANES technique isolates the absorption component coming from chemisorption of atoms or molecules on a sample by taking the difference between the XANES with and without the chemisorbed species, and thereby provides adsorbate information.

A fuel cell is a device that converts hydrogen or other fuel to electrical energy in a controlled and efficient way. They are already in use in many prototype cars. It is now possible for us to see things that have never been observed before in an operating fuel cell with the new ? XANES technique. This enables both the determination of atomic and molecular adsorption sites and coverage on small metal nanoparticles with the delta XANES, and correlation of that with the structural information obtained from the EXAFS. Both techniques can be applied to very complex systems such as in electrochemical cells, operating fuel cells and catalysts under reaction conditions.

For more news about The George Washington University, visit www.gwnewscenter.org.

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