Method and system for the combination of non-thermal plasma and metal/metal oxide doped γ-alumina catalysts for diesel engine exhaust aftertreatment system

Abstract

The present disclosure pertains to a system and method for treatment of oxygen rich exhaust and more specifically to a method and system that combines non-thermal plasma with a metal doped γ-alumina catalyst. Current catalyst systems for the treatment of oxygen rich exhaust are capable of achieving only approximately 7 to 12% NOreduction as a passive system and only 25–40% reduction when a supplemental hydrocarbon reductant is injected into the exhaust stream. It has been found that treatment of an oxygen rich exhaust initially with a non-thermal plasma and followed by subsequent treatment with a metal doped γ-alumina prepared by the sol gel method is capable of increasing the NOreduction to a level of approximately 90% in the absence of SOand 80% in the presence of 20 ppm of SO. Especially useful metals have been found to be indium, gallium, and tin.