�A fuel cell is a power generation device that converts energy into
electricity with very high efficiencies without combustion, flame,
noise or vibration,� Strasser said. �If a fuel cell is run on hydrogen
and air, as planned for automotive fuel cells, hydrogen and oxygen
molecules combine to provide electricity with water as the only
byproduct.�
The key to making a fuel cell work is a catalyst, which facilitates
the reaction of hydrogen and oxygen. The most common, but expensive,
catalyst is platinum. Currently, the amount of platinum catalyst
required per kilowatt to power a fuel cell engine is about 0.5 to 0.8
grams, or .018 to .028 ounces. At a cost of about $1,500 per ounce,
the platinum catalyst alone would cost between $2,300 to $3,700 to
operate a small, 100-kilowatt two- or four-door vehicle � a
significant cost given that an entire 100-kilowatt gasoline combustion
engine costs about $3,000. To make the transition to fuel cell-powered
vehicles possible, the automobile industry wants something better and
cheaper.
�The automobile companies have been asking for a platinum-based
catalyst that is four times more efficient, and, therefore, four times
cheaper, than what is currently available,� Strasser said. �That�s the
magic number.�
Strasser and his team, which includes Ratndeep
Srivastava, a graduate student, Prasanna Mani, a postdoctoral
researcher, and Nathan Hahn, a 2007 UH graduate, have met and,
seemingly, exceeded this �magic number.� The team created a catalyst
that uses less platinum, making it at least four times � and up to six
times � more efficient and cheaper than existing catalysts at
comparable power levels.
�We have found a low platinum alloy that we pre-treat in a special way
to make it very active for the reaction of oxygen to water on the
surface of our catalyst,� Strasser said. �A more active catalyst means
that we get more electricity, or energy, for the amount of platinum
used and the time it�s used for. With a material four to six times
more efficient, the cost of the catalyst has reached an important
target set by industrial fuel cell developers and the U.S. Department
of Energy.�
Although more testing of how the durability of this new catalyst
compares to pure platinum is necessary, the preliminary results look
promising.
�The initial results show that durability is improved over pure
platinum, but only longer-term testing can tell,� Strasser said.
Long-term results may take some time, but industry expert Hubert
Gasteiger, a leading scientist in fuel research with Aeta S.p.A. in
Italy, is already excited.
�The automotive cost targets, which were developed several years ago,
require that the activity of the available platinum catalysts would
need to be increased by a factor of four to six,� Gasteiger said. �The
novel catalyst concept developed by Professor Strasser�s group has
been demonstrated to provide an enhancement factor of greater than
four, and, thereby, are very promising materials to achieve the
platinum metals cost targets of typical hydrogen-oxygen automotive
fuel cells. This is a very exciting and new development, even though
more work is required to assure that the durability of these novel
catalysts is equally superior to the current carbon-supported platinum
catalysts.�
Strasser�s preliminary results and research have been published in the
October 2007 issues of Angewandte Chemie International Edition and
Journal of the American Chemical Society.
Sponsored by $1.5 million in grants from the U.S. Department of Energy,
National Science Foundation, major automotive fuel cell developers and
NASA through the Houston Advanced Research Center, Strasser hopes
companies will begin introducing fuel cell-powered cars within the
next decade.
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