Poisoning Effect Comparison of ZnCl ₂ and ZnSO ₄ on Mn‐Ce/AC Catalyst for Low‐Temperature SCR of NO

Abstract

Abstract In this study, the effect of different zinc salts (ZnCl 2 and ZnSO 4 ) on the deactivation of activated carbon(AC)‐based Mn−Ce catalysts and the poisoning mechanism of zinc salts on Mn−Ce/AC are comparatively studied. SEM, BET, XRD, XPS, H 2 ‐TPR, NH 3 ‐TPD and In‐situ DRIFT are used to characterize the physical and chemical changes of Mn−Ce/AC catalyst. The Selective Catalytic Reduction (SCR) activities of Mn−Ce/AC has a noticeable decline after loading zinc salts, and the highest NO conversion of Zn poisoning catalysts do not exceed 70 %. And the acid site is occupied by Zn 2+ on the catalyst, which affects the chemical adsorption of NH 3 and hinders the formation of the intermediate ‐NH 2 . Moreover, the decrease of Mn 4+ , reducibility of manganese oxide and acid sites are more serious on ZnC−Mn‐Ce/AC. Besides, loading ZnSO 4 can improve the content of Ce 3+ and O β on catalyst surface, which can mitigate the poisoning effects of ZnSO 4 on Mn−Ce/AC catalyst. Hence, ZnCl 2 displays a more serious poisoning effect on Mn−Ce/AC catalyst compared with ZnSO 4 . Then the probable mechanism model of ZnCl 2 and ZnSO 4 on Mn−Ce /AC catalyst is proposed and compared.