Hawaii
Energy Policy Forum > 2003
Articles
New catalyst for Hydrogen production may be a breakthrough
Paper Mill Sludge Used to Create Fuel Cell Catalyst
Elmhurst Ruralite
August 2003
MADISON, Wisconsin, June 27, 2003 (ENS) - Chemical
and biological engineers at the University of Wisconsin-Madison
say they have found a cost effective nickel-tin catalyst
that can replace the expensive metal platinum in a new process
for making hydrogen fuel from plants. Along with a second
innovation that purifies hydrogen for use in hydrogen fuel
cells, the catalyst offers new opportunities in a transition
from a world economy based on fossil fuels to one that is
based on hydrogen produced from renewable resources.
The
research was published in this week’s issue of
the journal “Science,” a publication of the American
Association for the Advancement of Science.
James Dumesic,
a professor of chemical and biological engineering, and
graduate students George Huber and John Shabaker, tested
more than 300 materials to find a nickel-tin-aluminum combination
that reacts with oxygenated hydrocarbons derived from biomass
to produce hydrogen and carbon dioxide without emitting
large amounts of unwanted methane.
"
Platinum is very effective, but it's also very expensive," said
Dumesic. "It's also problematic for large scale power
production because platinum is already in demand for use
as anode and cathode materials in hydrogen fuel cells.”
The
single step process uses temperature, pressure and a catalyst
to convert hydrocarbons such as glucose, the energy
source used by most plants and animals, into hydrogen,
carbon dioxide and gaseous alkanes, with hydrogen constituting
50
percent of the products.
More refined molecules, such as
ethylene glycol and methanol, are almost completely converted
to hydrogen and carbon dioxide
in the process. Because plants grown as fuel crops absorb
the carbon dioxide released by the system, the process
is greenhouse gas neutral.
Glucose is manufactured in the form
of corn syrup, but it can also be made from sugar beets,
or low cost biomass waste
streams like paper mill sludge, cheese whey, or wood waste.
While hydrogen yields are higher for more refined molecules,
Dumesic says glucose derived from waste biomass is likely
to be the more practical candidate for cost effective power
generation.
Because the Wisconsin process occurs in a liquid
phase at low reaction temperatures, the hydrogen is made
without vaporizing
water.
That represents a major energy savings compared to ethanol
production or conventional fossil fuel based hydrogen generation
methods that require water to be boiled away, the scientists
say.
The dramatic reduction in carbon monoxide emissions
achieved by the team's new process overcomes a technical
obstacle
in the efficient operation of hydrogen fuel cells. Carbon
monoxide poisons the electrode surfaces of the devices,
hampering their reliability.
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