MTL Annual Report

Combustion of fossil fuels, essential for electricity generation and vehicular propulsion, is generally incomplete, leading to harmful NO_x, CO, and unburned hydrocarbons emissions.  Great progress in minimizing such emissions has relied on the operation of “three-way catalysts” (TWCs), which utilize a combination of precious metals and metal oxides with the ability to take up or release oxygen for reduction/oxidation of pollutants (NO_x to N₂ plus CO and HC to CO₂ and H₂O, respectively).  In this project, we are investigating the rate at which oxygen-storage materials (OSM) exchange oxygen with the atmosphere and the magnitude of oxygen they store with the aid of geometrically well-defined thin film structures. Impedance spectroscopy, Kelvin probe, and thermogravimetric methods are used to determine electrochemical performance and oxygen-storage capabilities.  These properties, when correlated to actual TWC performance using a differential flow reactor, will allow for a more detailed understanding of performance criteria.