The enhancement for SCR of NO by NH sub(3) over the H sub(2) or CO pretreated Ag/ gamma -Al sub(2)O sub(3) catalyst

H sub(2) or CO pretreatment had been processed on the Ag/ gamma -Al sub(2)O sub(3) catalyst which significantly enhanced its NH sub(3)-SCR activity. The main purpose of this study was to prove that the impacts of pretreatment on silver species caused the enhancement. XRD, UV-vis, XPS, in situ FTIR and NO-TPD results showed the relationship between pretreatment, Ag species, NO sub(X) adsorption and NO sub(X) conversion. Extra nitrates were adsorbed on the Ag clusters which were produced by the pretreatment, thereby enhancing the activity. The reactivities between NO and NH sub(3) had been studied. The difference between CO-pretreatment and H sub(2)-pretreatment had also been discussed. Furthermore, the durability and stability of the pretreated sample were tested. Therefore, a modified Ag sub(2)O/Al sub(2)O sub(3 ) catalyst for NH sub(3)-SCR was researched.