CLEERS Teleconference: Andrew “Bean” Getsoian

Title: Next Generation Three Way Catalysts for Future, Highly Efficient Gasoline Engines.

Andrew “Bean” Getsoian, Ph.D. from Ford Motor Co.

Abstract:

The greater fuel efficiency of future gasoline engines is expected to produce new challenges for emissions control. Exhaust temperatures at low loads will become cooler, requiring greater catalytic activity at lower temperatures. At the same time, exhaust temperatures at high loads will remain high; low temperature activity must therefore be improved without compromising thermal durability. To address these challenges, Ford Motor Company, Oak Ridge National Laboratory, and the University of Michigan have recently completed a DOE-sponsored collaboration with the stated goal of developing next generation three way catalysts capable of achieving 90% conversion of CO, hydrocarbons, and NOx at 150°C while still meeting current TWC thermochemical durability requirements.

This talk will comprise two sections. In the first, we will discuss TWC development work at Ford, which led us to “overlayer catalysts” in which a stabilized alumina core is covered by a monolayer of a promoter oxide and then loaded with a Pd or Rh active phase. After accelerated aging, the resulting catalysts exhibit T90s for CO, hydrocarbons, and NOx that are 50°C, 90°C, and 110°C lower than those obtained over a commercial catalyst. Characterization by electron microscopy, DRUVS, and EXAFS suggests that high dispersion of the promotor species is key to its stability and promotional role.

In the second section, we will discuss sensitivity of T90s for hydrocarbons and NO during light-off to small variations in air-fuel ratio. These effects, first observed over Rh overlayer catalysts, are quite general and provide important insights into the relative importance of oxidation and steam reforming reactions during three way catalysis.