Leaner and cleaner

In a finding that provides an important boost to automobile emissions control technology, College of Engineering researchers have discovered a new way to operate pollution-dampening catalytic converters without the need for expensive noble metals.

The novel formulation is designed for a relatively new automobile engine technology that provides for high fuel efficiency. Such “lean burn” engines, which can save up to 20 percent 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. These new engines require new catalysts to reduce emissions because the existing catalysts do not work under the exhaust conditions the engines create.

The formulation developed by Jochen A. Lauterbach, associate professor of chemical engineering, and his 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 oxidizing metallic element. “This has proved to be superior in performance, and a lot cheaper, than the best catalytic converter materials known,” Lauterbach says.

The finding, which is the result of more than two years of research, was highlighted in a recent issue of Chemical and Engineering News and was the subject of a paper in the professional journal Catalysis Communications.

The idea for this new class of catalysts was drawn from research undertaken by Toyota Motor Corp., and Lauterbach says the concept intrigued his research team.

“We began by taking a fundamental science approach,” he says. “Since then, we have moved over to the applied side, while still working on the fundamentals. We continue to be very interested in why these materials do what they do.”

The 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 individually.

“The idea is to look at multiple materials in parallel, rather than one at a time,” Lauterbach says. “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.”

The research team was just the second academic group in the United States to begin work in combinatorial catalysis, and it remains one of the leading groups in the nation in that field.

“As a University with a large educational component, it is important to educate students in these novel ways to conduct research,” Lauterbach says. “We are training students to go to industry with this new way of thinking.”

The researchers 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. They have found that an alumina-supported catalyst containing 5 percent cobalt and 15 percent barium is just as effective as conventional formulations that contain 1 percent platinum.

Furthermore, the UD scientists have found that by adding platinum to the cobalt-barium catalyst, they can produce a material with twice the nitrogen oxide storage capacity of traditional platinum-based catalysts.

“Our primary finding, really, is in performance,” Lauterbach says. “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.”

The research team now is working to optimize the composition of the material, in terms of both cost and long-term stability. Lauterbach says he believes the findings should be of great interest to both government and industry.

“The U.S. 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 says. “If the technology is there and you can save fuel, it presents an opportunity to reduce dependence on foreign oil.”

The National Science Foundation is supporting the research. The team includes engineering graduate students Rohit Vijay and Ben Feist, research associate Christopher M. Snively and student researcher Ben Rogers, EG ’05.

Lauterbach came to UD in 2002 from Purdue University, where he won the National Science Foundation’s prestigious Faculty Early Career Development Award in 1998. He earned a bachelor’s degree from the University of Bayreuth, Germany, and his doctorate from the Free University of Berlin, Germany.  

—Neil Thomas, AS ’76