[Paleopsych] Nanotechnology could promote hydrogen economy

[Steve Hovland]

Contact: Carl Blesch
cblesch at ur.rutgers.edu <mailto:cblesch at ur.rutgers.edu>
732-932-7084 x616
Rutgers, the State University of New Jersey <http://www.rutgers.edu>
NEW BRUNSWICK/PISCATAWAY, N.J. - Say "nanotechnology" and people are likely 
to think of micro machines or zippy computer chips. But in a new twist, 
Rutgers scientists are using nanotechnology in chemical reactions that 
could provide hydrogen for tomorrow's fuel-cell powered clean energy 
vehicles.
In a paper to be published April 20 in the Journal of the American Chemical 
Society, researchers at Rutgers, The State University of New Jersey, 
describe how they make a finely textured surface of the metal iridium that 
can be used to extract hydrogen from ammonia, then captured and fed to a 
fuel cell. The metal's unique surface consists of millions of pyramids with 
facets as tiny as five nanometers (five billionths of a meter) across, onto 
which ammonia molecules can nestle like matching puzzle pieces. This sets 
up the molecules to undergo complete and efficient decomposition.
"The nanostructured surfaces we're examining are model catalysts," said Ted 
Madey, State of New Jersey professor of surface science in the physics 
department at Rutgers. "They also have the potential to catalyze chemical 
reactions for the chemical and pharmaceutical industries."
A major obstacle to establishing the "hydrogen economy" is the safe and 
cost-effective storage and transport of hydrogen fuel. The newly discovered 
process could contribute to the solution of this problem. Handling hydrogen 
in its native form, as a light and highly flammable gas, poses daunting 
engineering challenges and would require building a new fuel distribution 
infrastructure from scratch.
By using established processes to bind hydrogen with atmospheric nitrogen 
into ammonia molecules (which are simply one atom of nitrogen and three 
atoms of hydrogen), the resulting liquid could be handled much like today's 
gasoline and diesel fuel. Then using nanostructured catalysts based on the 
one being developed at Rutgers, pure hydrogen could be extracted under the 
vehicle's hood on demand, as needed by the fuel cell, and the remaining 
nitrogen harmlessly released back into the atmosphere. The carbon-free 
nature of ammonia would also make the fuel cell catalyst less susceptible 
to deactivation.
When developing industrial catalysts, scientists and engineers have 
traditionally focused on how fast they could drive a chemical reaction. In 
such situations, however, catalysts often drive more than one reaction, 
yielding unwanted byproducts that have to be separated out. Also, 
traditional catalysts sometimes lose strength in the reaction process. 
Madey says that these problems could be minimized by tailoring 
nanostructured metal surfaces on supported industrial catalysts, making new 
forms of catalysts that are more robust and selective.
In the journal article, Madey and postdoctoral research fellow Wenhua Chen 
and physics graduate student Ivan Ermanoski describe how a flat surface of 
iridium heated in the presence of oxygen changes its shape to make uniform 
arrays of nanosized pyramids. The structures arise when atomic forces from 
the adjacent oxygen atoms pull metal atoms into a more tightly ordered 
crystalline state at temperatures above 300 degrees Celsius (or 
approximately 600 degrees Fahrenheit). Different annealing temperatures 
create different sized facets, which affect how well the iridium catalyzes 
ammonia decomposition. The researchers are performing additional studies to 
characterize the process more completely.
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The Rutgers researchers are conducting their work in the university's 
Laboratory for Surface Modification, which provides a focus for research 
into atomic-level phenomena that occur on the surface of solids. It 
involves the overlapping disciplines of physics, chemistry, materials 
science and engineering. Their work is supported in part by grants from the 
U. S. Department of Energy's Office of Basic Energy Sciences.