Nanotechnology Now - Press Release: Gold, Copper Nanoparticles Take Center Stage in the Search for Hydrogen Production Catalysts

Home > Press > Gold, Copper Nanoparticles Take Center Stage in the Search for Hydrogen Production Catalysts

Abstract:
X-ray studies at the U.S. Department of Energy's (DOE)
Brookhaven National Laboratory are pointing the way to less costly
and more efficient catalysts for improving the performance of fuel
cells. The studies, which will be presented by Brookhaven chemist
Jose Rodriguez at the 233rd National Meeting of the American Chemical
Society, show that copper can be substituted for gold in reactions
that keep fuel cells functioning longer while eliminating unwanted
byproducts.

Gold, Copper Nanoparticles Take Center Stage in the Search for Hydrogen Production Catalysts

CHICAGO, IL | Posted on March 28th, 2007

With the goal of efficient fuel cell operation in mind, researchers
first need to turn their attention to hydrogen, which is one of the
leading energy sources being investigated by scientists sponsored by
the DOE as part of its mission to ensure the nation's future energy
needs. A major problem facing today's most promising fuel-cell
technologies is that the same hydrogen-rich materials feeding the
reaction often contain high levels of carbon monoxide (CO), which is
formed during hydrogen production. Within a fuel cell, CO "poisons"
the expensive platinum catalysts that convert hydrogen into
electricity, deteriorating their efficiency over time and requiring
their replacement.

Rodriguez will discuss how the use of gold and copper nanoparticles
might provide a solution to this problem at 8:30 a.m. Central Time
(9:30 a.m. Eastern Time) on Wednesday, March 28, 2007, in room S404D,
Level 4, at McCormick Place South, Chicago, Illinois.

"We're trying to find a catalyst that achieves two things: produces
hydrogen while removing a large amount of CO," Rodriguez said.

One way to eliminate the CO byproduct is to combine it with water to
produce hydrogen gas and carbon dioxide in a process known as the
"water-gas shift" reaction. With the assistance of proper catalysts,
the water-shift reaction can convert nearly 100 percent of the CO
into carbon dioxide. Using catalyst characterization techniques at
Brookhaven's National Synchrotron Light Source (NSLS), Rodriguez and
coworkers Jonathan Hanson and Jan Hrbek found that nanoparticles of
either gold or copper, supported on a metal, can perform this
catalytic role. In particular, they found that the greatest catalytic
activity is achieved with extremely small nanoparticles -- less than
4 nanometers (4 billionths of a meter) -- supported on the metal
cerium oxide, or ceria.

"Metal nanoparticles alone are not able to do the catalysis,"
Rodriguez said. "But when you put them on the ceria, you see
tremendous catalytic activity."

At the nanoscale, gold has long been known to exhibit chemical
reactivity that makes it a potent catalyst. The problem, however,
comes with its hefty price tag. "We wanted a material that was less
expensive," Rodriguez said. "We wanted to see if we could replace the
gold with copper." Using x-ray diffraction, absorption, and
spectroscopy studies at the NSLS, Rodriguez's group showed that the
substitution is indeed possible. Although gold nanoparticles continue
to show the greatest catalytic activity, copper is almost as reactive
and its cost is much lower.

This research was funded by the Office of Basic Energy Sciences
within the DOE's Office of Science.

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About Brookhaven National Laboratory
One of ten national laboratories overseen and primarily funded by the
Office of Science of the U.S. Department of Energy (DOE), Brookhaven
National Laboratory conducts research in the physical, biomedical,
and environmental sciences, as well as in energy technologies and
national security. Brookhaven Lab also builds and operates major
scientific facilities available to university, industry and
government researchers. Brookhaven is operated and managed for DOE's
Office of Science by Brookhaven Science Associates, a
limited-liability company founded by the Research Foundation of State
University of New York on behalf of Stony Brook University, the
largest academic user of Laboratory facilities, and Battelle, a
nonprofit, applied science and technology organization. Visit
Brookhaven Lab's electronic newsroom for links, news archives,
graphics, and more: http://www.bnl.gov/newsroom .

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Brookhaven National Laboratory
Upton NY 11973

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