New synthetic protocols to manipulate Si/Al ratios of small pore zeolites hold promise to find better selective NO reduction catalyst using NH as reducing agent (NH-SCR). zeolite as NH-SCR catalyst is currently impeded by the insufficient hydrothermal stability owing to the low Si/Al ratio. In this contribution, we report the synthesis of zeolite using N,N-(1,4-phenylenebis(methylene))bis(N,N,N-triethylammonium) as organic structure directing agent (OSDA) to increase the framework Si/Al ratio to 7.8, giving rise to a marked enhancement of hydrothermal stability to withstand hydrothermal aging at 850 °C for up to 10 h. The increase in Si/Al ratio for zeolite minimizes catalytic cycle driven by Brønsted acid site and broadens high temperature operation window (150–515 °C) for Cu-exchanged catalyst. Moreover, the hydrothermally aged Cu-AFX catalyst exhibits comparable catalytic activity to that of the fresh catalyst owing to Cu predominant distribution close to the 6-MR.

中文翻译：

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使用刚性双季烷基铵结构导向剂生成富硅 AFX 沸石，实现 NH3 稳定选择性催化还原 NOx

控制小孔沸石硅铝比的新合成方案有望找到使用 NH 作为还原剂的更好选择性 NO 还原催化剂 (NH-SCR)。沸石作为NH-SCR催化剂目前由于Si/Al比低而导致水热稳定性不足而受到阻碍。在这篇文章中，我们报道了使用 N,N-(1,4-亚苯基双(亚甲基))双(N,N,N-三乙基铵)作为有机结构导向剂 (OSDA) 来合成沸石，以增加 Si/Al 骨架比率达到 7.8，水热稳定性显着增强，可承受 850 °C 的水热老化长达 10 小时。沸石硅铝比的增加最大限度地减少了布朗斯台德酸位点驱动的催化循环，并拓宽了铜交换催化剂的高温操作窗口（150-515°C）。此外，由于Cu的主要分布接近6-MR，水热老化的Cu-AFX催化剂表现出与新鲜催化剂相当的催化活性。