Optimized Synthesis of High‐Performance Cu‐Y zeolite Catalyst for NH ₃ ‐SCR via Ion Exchanged with Relatively Inexpensive NH ₄ Cl as an Alternative to NH ₄ NO ₃

ABSTRACT The preparation of low‐cost, environmentally friendly, and exceptional activity supported zeolite catalysts is still a major challenge in the NH 3 ‐SCR field. In this study, Cu‐Y‐x (x represents the concentration of NH 4 Cl, x = 0.3, 0.6, and 0.9) zeolite was achieved by initial exchanged of Na‐Y with the economical NH 4 Cl, a more cost‐efficient and safe option relative to NH 4 NO 3 followed by copper salt treatment, whereas the reference sample Cu‐Y‐0 was prepared by direct exchange of Na‐Y with metal salts. Furthermore, their NH 3 ‐SCR activity and the resistance of SO 2 /H 2 O were studied. Additionally, a study on the impact of NH 4 Cl concentration on NH 3 ‐SCR activity was also conducted. XRD and SEM and so on results exhibited that Cu‐Y was successfully prepared. H 2 ‐TPR and XPS results displayed that Cu‐Y‐0 had good redox ability and a relatively high amount of Cu 2+ . The NH 3 ‐SCR results exhibited that the exchange with NH 4 Cl broadened the reaction temperature window, the optimal concentration of NH 4 Cl ion exchange was 0.6 mol/L due to the excessive Cl − simultaneously impeding the adsorption of NO x and Cu‐Y‐0.6 displayed good NH 3 ‐SCR performance at temperatures ranging from 200°C to 350°C (the NO x conversion was more than 91.5%). Most notably, Cu‐Y‐0 and Cu‐Y‐0.6 exhibited good resistance of H 2 O. Cu‐Y‐0.6 showed better performance than that of Cu‐Y‐0 in the presence of SO 2 because of the presence of the competitive adsorption between Cl − ions and SO 2 for Cu‐Y‐0.6. In addition, it may be due to Cl − creating new acidic sites. This sheds light on the preparation of NH 3 ‐SCR catalysts with excellent activity.