초록 ▼

A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then

A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO2, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N2O was not detected (detection limit: 0.6 percent N2O).

대표청구항 ▼

What is claimed is: 1. A method for improving the low temperature performance of a lean NOx trap comprising putting a catalyst upstream of a lean NOx trap, the catalyst comprising a medium pore zeolite impregnated with iron, cerium, and manganese, and then contacting the catalyst with NO and oxygen

What is claimed is: 1. A method for improving the low temperature performance of a lean NOx trap comprising putting a catalyst upstream of a lean NOx trap, the catalyst comprising a medium pore zeolite impregnated with iron, cerium, and manganese, and then contacting the catalyst with NO and oxygen, whereby the catalyst substantially oxidizes the NO to NO2 to produce a NO2 enriched stream that improves the low temperature performance of the lean NOx trap.