Effect of SO sub(2) On the Activity of Ag/ gamma -Al sub(2)O sub(3) Catalysts for NO sub(x) Reduction in Lean Conditions

Findings are presented from experiments investigating the lean-NO sub(x) performance and the effects of SO sub(2) on silver-doped gamma alumina catalysts using simulated diesel exhaust. These experiments were implemented to improve understanding of the active site and the factors that contribute to poisoning of the catalyst. Samples of the catalytic materials considered in the project were prepared via impregnation of gam-alumina with silver nitrate or silver sulfate using the incipient wetness method. For tests implemented in the absence of SO sub(2), a formulation based on 2 wt.% Ag/Al sub(2)O sub(3) proved to be the best for NO sub(x) reduction. Performance of the catalysts was strongly impacted by the presence of SO sub(2) in the feed stream. Causes of these variations in the data are discussed.