By Tina Hilding, Voiland College of Engineering & Architecture
PULLMAN, Wash. – Volkswagen’s disgrace last year for altering software to pass emissions tests highlighted a problem for the auto industry: People want vehicles that are both non-polluting and fuel efficient, but they are difficult to produce with current technologies.
Washington State University and Tufts University researchers have developed a model of an important catalyst that is key to solving that challenge. It could lead to cleaner, fuel efficient vehicles as well as advances in industrial processes for common products. The work is featured on the cover of today’s Journal of Physical Chemistry.
Catalysts play an important role in a variety of industries, said Jean-Sabin McEwen, assistant professor in WSU’s Gene and Linda Voiland School of Chemical Engineering and Bioengineering. In automobiles, researchers have struggled to develop a system that seamlessly and easily converts pollutants like nitrogen oxides and carbon monoxide to less harmful nitrogen and carbon dioxide – without using a lot of energy.
The best catalysts don’t work well at low temperatures, which is why a car puts out more pollution for the first few miles as it warms up.
“These problems are really hard,” McEwen said. “If you want to design better catalysts, you have to understand how the catalysts tick in the first place. We are working to understand the reactions and are developing detailed explanations of what’s going on.”
The WSU and Tufts team developed a model of a common copper catalyst and, in particular, a thin layer on the surface of the copper that contains oxygen. Copper is often used as a catalyst because it is fairly inexpensive and performs well. The copper oxide layer influences reaction rates, but it is complex and poorly understood.
“We’re not just making copper rust,’’ McEwen said. “It’s a very complicated structure. We’re working at the nanometer level, building the structures atom by atom.’’
The researchers developed a complex theoretical model of the catalyst and confirmed its validity with atomic-scale images provided by professor Charlie Sykes’ research group at Tufts. They worked with the U.S. Department of Energy’s Environmental Molecular Science Laboratory at the Pacific Northwest National Laboratory, using a super computer for the complex calculations required.
They can now use the theoretical model to make atomic level tweaks and predict the catalyst’s behavior.
“We must have a well-defined model to be sure of what we’re looking at,’’ said McEwen. “It’s quite exciting to have this synergy of experimental and theoretical results that match.’’
The researchers hope to investigate ways to improve the catalytic reactions, in particular by studying the addition of single precious metal atoms on the catalyst surface.
The WSU work was funded by the National Science Foundation EAGER program under grant No. CBET-1552320, and the work at Tufts was supported by the U.S. Department of Energy BES under grant No. DE-FG02-05ER15730.
Contacts:
Jean-Sabin McEwen, WSU Gene and Linda Voiland School of Chemical Engineering and Bioengineering, 509-335-8580, js.mcewen@wsu.edu
Tina Hilding, WSU Voiland College of Engineering and Architecture communications, 509-335-5095, thilding@wsu.edu
