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Materials Science at Oregon State University

Some Current and Future Challenges for Catalytic Vehicle Emission Control - PLEASE NOTE - Seminar is at 5pm in LPSC 402

Date: Thursday, Oct 16th
Presenter: Charles H.F. Peden, Ph.D., Institute for Integrated Catalysis, Pacific Northwest National Laboratory


The abatement of environmentally harmful compounds (e.g., hydrocarbons (HC), oxides of nitrogen (NOx) and sulfur (SOx), and CO), emitted from mobile or stationary power sources, has been a remarkable success story for the catalysis research and development community [1]. In particular, for mobile (vehicle exhaust emission control) applications, the “three-way” catalyst that is the active component of the “catalytic converter”, a standard component on automobiles in the US and Europe for over 30 years, has contributed to a remarkable drop in emissions of CO, HC and NOx from gasoline-powered vehicles. We now take for granted the dramatic improvements that the introduction of the catalytic converter technology has made in air quality and, correspondingly, human health. However, this technology is not suitable for application on so-called “lean-burn” engines that operate at high air/fuel ratios, including diesel-powered vehicle engines. Although these engine technologies are inherently more fuel efficient than “stoichiometric” gasoline engines, their wide-spread application for vehicles has been limited by the inability of the three-way catalyst to reduce NOx emissions at these high air/fuel ratios. As such, in the last 10-15 years a significant focus has been on this problem of “lean-NOx” emission control. Again, significant achievements have been realized with the very recent commercialization of two new nano-materials-based catalytic emission control applications for diesel-powered vehicles: the NOx storage/reduction (NSR) catalysts and the selective catalytic reduction (SCR) with ammonia using metal-exchanged zeolites. Because these are such newly introduced technologies, many challenges remain to improve performance, enhance stability, and lower costs. Indeed, many of the practical concerns with these new “lean-NOx” catalyst technologies stem from a relatively poor fundamental understanding of catalyst structure/activity and reaction mechanisms. More profoundly, highly novel operating modes for internal combustion engines (ICEs) are being researched in order to meet the very stringent new demands for fuel efficiency (e.g., US “CAFE” standards for average miles/gallon are scheduled to increase dramatically over the next 10-15 years). These new ICE engine operation modes, while highly fuel-efficient, result in much lower exhaust temperatures than current engines; temperatures so low that it is hard to imagine how the current catalytic emission control technologies will be able to function [2]. Thus, both ‘evolutionary’ and ‘revolutionary’ technology development challenges can be foreseen for the catalyst research community. This presentation will highlight both the challenges for currently practiced technologies, and some of the significant new catalytic materials and process challenges that will need to be addressed in the near future.

[1] R.M. Heck and R.J. Farrauto, “Catalytic Air Pollution Control: Commercial Technology.” Van Nostrand Reinhold (New York) 1995.
[2] M. Zammit, C.L. DiMaggio, C.H. Kim, C.K. Lambert, G.G. Muntean, C.H.F. Peden, J.E. Parks, and K. Howden, “Future Automotive Aftertreatment Solutions: The 150C Challenge Workshop Report.” U.S. Drive Report (Southfield, MI) 2013, PNNL-22815.

Chuck Peden is Associate Director of the Institute for Integrated Catalysis at Pacific Northwest National Laboratory (PNNL). He is also a Laboratory Fellow, and manages and participates in multiple technical projects within the Physical Sciences Division at PNNL. He joined PNNL in 1992 following a nine-year tenure at Sandia National Laboratories in Albuquerque, New Mexico, as a Senior Member of the Technical Staff in the Inorganic Materials Chemistry Department. Peden’s main research interests are in the surface and interfacial chemistry of inorganic solids; in particular, the heterogeneous catalytic chemistry of metals and oxides with an emphasis on reaction mechanisms and materials structure/function relationships. He is best known as a leader in the development of the mechanisms of automobile exhaust catalytic reactions. After graduating with distinction from California State University, Chico with a B.S. in chemistry, Peden completed his Ph.D. in physical chemistry at the University of California, Santa Barbara under the direction of Ralph G. Pearson. He then spent two years as a postdoctoral associate with D. Wayne Goodman at Sandia National Laboratories in Albuquerque, New Mexico before joining the scientific staff there. Peden has written or contributed to more than 250 peer-reviewed publications (H-factor > 40) and 4 issued U.S. patents on topics such as automobile exhaust catalysis, hydrocarbon reforming on bimetallic catalysts, the structure of hydroprocessing catalysts, the synthesis and characterization of novel supported solid acid catalysts, and the structure and chemistry of oxide surfaces. He is a member of the American Chemical Society, the American Institute of Chemical Engineers, the Society of Automotive Engineers, and the North American Catalysis Society. Peden was elected a Fellow of the American Vacuum Society in 2000, and the American Association for the Advancement of Science in 2009 and the American Chemical Society in 2012. He currently serves as Secretary of the ACS Catalysis Science and Technology Division.