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In this study, a series of K species or/and SO 2 poisoned Mn-Ce doped CuX (MCCX) catalysts were prepared from waste blast furnace slag (BFS), and the influence mechanism of K species or/and SO 2 poisoning on the catalysts in low-temperature NH 3 -SCR process was investigated. The results demonstrated that MCCX-KCl catalyst had poorer NO conversion than MCCX-K 2 O below 200 °C, and the co-existence of K species and SO 2 considerably inhibited NO conversion. Aggregation of the Cu active component might also be facilitated by co-poisoning with K species and SO 2. Furthermore, K species and SO 2 co-poisoned catalysts showed fewer isolated Cu2+ species and Mn4+ species than that of K-poisoned catalysts, indicating a decrease in active sites after the addition of SO 2. The co-effect of K 2 O/KCl and SO 2 species impaired the redox capacity and decreased the surface acidity than K-poisoned catalysts to a greater extent. Nevertheless, K-poisoning had little effect on the surface intermediates during SCR reaction process, and K-poisoned catalysts followed both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanism. However, MCCX-KCl-SO 2 and MCCX-K 2 O-SO 2 catalysts contained fewer nitrate species, indicating that the co-effect of K species and SO 2 impeded the reaction between NO + O 2 species and pre-NH 3 species, thereby resulting in poor low-temperature NH 3 -SCR activity. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, CuX zeolite supported Mn and/or Ce oxides catalysts were synthesized by combining ion exchange and impregnation methods, and the zeolite X was generated using blast furnace slag (BFS). Doping Mn-Ce oxides onto the CuX catalyst, which has excellent resistance to SO 2 +H 2 O, improved the catalyst's activity for NH 3 -SCR at lower temperature. In addition, electron transfer from Mn4+ to Ce3+ and Cu2+ was enhanced, and the concentration of isolated Cu2+ and chemisorbed oxygen species was higher in the Mn-Ce/CuX catalyst. Also, the Mn-Ce/CuX catalyst provided excellent SCR activity because of its high acid capacity, which allowed it to provide extra acid sites, and its high redox ability, which enhanced the re-oxidized and re-reduced cycles. Additionally, produced sulfates on the catalyst surface after SO 2 and H 2 O poisoning might occupy Cu2+ active sites and affect the SCR process by competing with acid sites, nitrate species and intermediates on the Mn-Ce/CuX catalyst. [Display omitted] • Mn or Ce/CuX catalysts were prepared successfully from blast furnace slag. • Effects of Cu sites and Mn-Ce addition on the properties of the catalyst were analyzed. • Relationship between the physicochemical properties and catalytic activities of the catalysts was revealed. • Mn-Ce/CuX catalyst had excellent low-temperature NH 3 -SCR activity and SO 2 or H 2 O resistance. [ABSTRACT FROM AUTHOR]