Cu-SSZ-50 zeolite is considered as a promising candidate for NH-SCR catalysts. However, its hydrothermal stability is unsatisfactory, which limiting its application. In this study, the hydrothermal stability of Cu-SSZ-50 catalyst was remarkably improved by the introduction of Fe. Specifically, The NO conversion of Fe-Cu-SSZ-50 was elevated from ∼25 % to ∼80 % at 200 ℃ in the NH-SCR reaction after the hydrothermal aging process. H-TPR, EPR, NH-TPD, UV-Vis, XPS, TEM, NMR and DRIFTS were carried out to investigate the changes in the active sites and framework structure of the catalysts brought about by hydrothermal aging. The characterization results revealed that FeO in the fresh samples underwent re-dispersion into smaller nanoclusters and also transformed into active Fe ions during the hydrothermal aging process. This process inhibited the formation of inactive CuAlO, thereby increasing the quantity of active Cu sites in the aged catalyst and mitigating dealumination of the framework, ultimately enhancing the hydrothermal stability.

中文翻译：

---

通过水热处理时引入的 Fe 的再分散来增强 Cu-SSZ-50 NH3-SCR 催化剂的水热稳定性

Cu-SSZ-50 沸石被认为是 NH-SCR 催化剂的有前途的候选者。但其水热稳定性较差，限制了其应用。在这项研究中，Fe的引入显着提高了Cu-SSZ-50催化剂的水热稳定性。具体而言，水热老化过程后，在 NH-SCR 反应中，Fe-Cu-SSZ-50 在 200 ℃ 下的 NO 转化率从~25% 提高到~80%。通过H-TPR、EPR、NH-TPD、UV-Vis、XPS、TEM、NMR和DRIFTS研究了水热老化对催化剂活性位点和骨架结构的变化。表征结果表明，新鲜样品中的 FeO 重新分散成更小的纳米团簇，并在水热老化过程中转化为活性 Fe 离子。该过程抑制了惰性 CuAlO 的形成，从而增加了老化催化剂中活性 Cu 位点的数量，并减轻了骨架的脱铝，最终提高了水热稳定性。