The catalytic properties of iron-exchanged UZM-35, beta, LTA, and SSZ-13 zeolites with similar Si/Al and Fe/Al ratios (8.9-12 and 0.35-0.37, respectively) and their hydrothermally aged forms at 1023-1173 K are compared in NH₃-SCR. When fresh, the low-temperature (< 573 K) activity of Fe-UZM-35 is considerably better than the other three iron-exchanged zeolite catalysts. Unlike those in fresh Fe-beta, Fe-LTA, and Fe-SSZ-13, the iron species in fresh Fe-UZM-35 were found to be mainly present as isolated extraframework Fe³⁺ ions which may be responsible for the high low-temperature SCR activity. However, while hydrothermal aging at 1173 K led to a notable decrease in activity of all zeolite-supported iron catalysts, the extent of activity decrease differs according to the structure type of zeolite supports. The overall results of this study strongly suggest that zeolite framework topology is a key factor governing the activity and durability of zeolite-supported iron catalysts for NH₃-SCR.

Si / Al和Fe / Al比相似（分别为8.9-12和0.35-0.37）的铁交换UZM-35，β，LTA和SSZ-13沸石的催化性能及其在1023-1173的水热时效形式在NH ₃ -SCR中比较K。新鲜时，Fe-UZM-35的低温（<573 K）活性明显优于其他三种铁交换沸石催化剂。与新鲜的Fe-β，Fe-LTA和Fe-SSZ-13中的铁不同，新鲜Fe-UZM-35中的铁物种主要以孤立的框架外Fe ^{3+的形式存在。}可能导致高低温SCR活性的离子。然而，尽管在1173K下的水热老化导致所有沸石负载的铁催化剂的活性显着降低，但是活性降低的程度根据沸石载体的结构类型而不同。这项研究的总体结果有力地表明，沸石骨架拓扑是控制NH ₃ -SCR沸石负载铁催化剂的活性和耐久性的关键因素。