PNNL

Abstract

NOx reduction exceeding 90% has been demonstrated for a simulated exhaust stream in bench scale experiments and in engine slip-stream tests using a plasma treatment step followed by catalytic lean-NOx reduction. The effect of reducing agent on catalysis has been probed in some detail and results show that a variety of hydrocarbons can be used to reduce NOx. It is also demonstrated that optimal catalyst formulation, based on silver-doped g-alumina, is highly dependent on the hydrocarbon species. Fuel-like hydrocarbons such as isooctane can give high activity, but the level of silver in the catalyst must be increased above levels typically used for propene or other light hydrocarbons. Comparison between bench data and steady-state engine testing conducted in 2001 will also be provided.