Method for reducing automotive NOx emissions in lean burn internal combustion engine exhaust using a transition metal-containing zeolite catalyst which is in-situ crystallized

摘要

A method is provided for reducing NOx for high flow applications such as NOx abatement in an exhaust gas from an internal combustion engine operating under lean burn conditions wherein NOx is reduced by hydrocarbon reductants. The method employs a hydrothermally stable catalyst comprising transition metal-containing ZSM-5 which is prepared by in-situ crystallization of an aggregate comprising ZSM-5 seeds, silica, and a crystalline silicate.