28-02-05
In a finding that provides an important boost to vehicle emissions control
technology, a University of Delaware research team has discovered a novel
formulation to operate pollution-dampening catalytic converters without the need
for expensive noble metals. These new engines require new catalysts because the existing catalysts do not
work under the exhaust conditions the engines create. The formulation developed
by Jochen A. Lauterbach, UD associate professor of chemical engineering, and
colleagues is both cheaper and more effective than the current means of
catalytic conversion, which relies on the use of costly platinum in the storage
and reduction of nitrogen oxides in the emissions. The UD research team has
achieved positive results by using the less expensive cobalt as an oxidising
metallic element. Successful combinations The UD group can test 16 catalysts at once, studying the effect of small
concentrations of manganese, iron and cobalt on the performance of nitrogen
oxide storage and reduction catalysts. The scientists found that an alumina-supported
catalyst containing five percent cobalt and 15 % barium was just as effective as
conventional formulations that contain one percent platinum. The UD scientists now are working to optimise the composition of the
material, in terms of both cost and long-term stability.
Source: The Engineer OnlineResearch team discovers new formula for cheaper catalysts
The novel formulation is designed for a relatively new vehicle engine technology
that provides for high fuel efficiency. Such lean burn engines, which can save
up to 20 % on fuel consumption over engines now in use, are being road tested in
several countries, including South Africa and Japan, but they are not yet on the
market.
"This has proved to be superior in performance, and a lot cheaper, than the
best catalytic converter materials known," Lauterbach said.
The UD team is a pioneer in combinatorial materials science, a method by which
the engineers can look at many potential catalysts at once rather than going
through the laborious process of studying the materials one by one.
"The idea is to look at multiple materials in parallel, rather than one at
a time," Lauterbach said. "Now we can look at anywhere from a dozen to
a hundred materials in the same amount of time as we previously could look at
one. As a result, we can look at material compositions that we wouldn't have
been able to study before, simply because of the time involved."
Furthermore, the UD scientists found that by adding platinum to the
cobalt-barium catalyst they could produce a material with twice the nitrogen
oxide storage capacity of traditional platinum-based catalysts.
"Our primary finding, really, is in performance," Lauterbach said.
"Using the cheaper material, the performance is equal to the most expensive
state-of-the-art equipment. And, if you add the higher priced materials, you see
a substantial increase in performance over what is shown in the most recent
literature."
Lauterbach said he believes the findings should be of great interest to both
government and industry.
"The US government is funding research on hydrogen fuel, which might save
us 50 years from now but won't make us less dependent on foreign oil in the next
few years," he said. "If the technology is there and you can save
fuel, it presents an opportunity to reduce dependence on foreign oil."