The origin of the beneficial effects of post-treatment processing with HNO₃ and NH₄NO₃ solutions on the catalytic performance of copper-amine templated zeolites used in the NH₃-SCR reaction was investigated. By careful design and optimization of the dual-treatment procedure (HNO₃-NH₄NO₃), Cu-SSZ-13 catalysts were obtained using Cu-TEPA as a template that exhibited NOx conversion above 90% in a wide temperature window from 250 to 450 ℃ with GHSV of ∼ 400,000 h^-1, even after hydrothermal aging at 750 and 800 ℃. The results of XRD and H₂-TPR indicated that the HNO₃ post-treatment adjusts the zeolite crystallinity and optimizes the copper species distribution in Cu-SSZ-13 catalysts. Further treatment with NH₄NO₃ reduces the Cu/Al ratios effectively and avoids the accumulation of Cu²⁺ ions to form CuOx clusters during hydrothermal aging. We investigated the influence of Cu²⁺ on the hydrothermal stability of Cu-SSZ-13, and two opposing effects were found. Cu²⁺ ions inhibit dealumination of the SSZ-13 zeolite structure, while excessive quantities of them easily accumulate to form CuOx clusters, leading to collapse of long-range order in the zeolite structure during hydrothermal aging. Before the zeolite structure collapses, Cu-SSZ-13 catalysts with high Cu loading exhibit higher NH₃-SCR activity due to the preservation of more active Cu²⁺. However, Cu-SSZ-13 catalysts totally lose deNOx activity in NH₃-SCR once the zeolite structure collapses. To guarantee both the activity for NOx reduction and hydrothermal tolerance, the optimal Cu loading (Cu/Al = 0.22∼0.31, here) and structural stability of in-situ synthesized Cu-SSZ-13 should be carefully tuned by HNO₃ and NH₄NO₃ treatment.

研究了用HNO ₃和NH ₄ NO ₃溶液进行后处理对NH ₃ -SCR反应中使用的铜胺模板沸石的催化性能的有益影响的根源。通过精心设计和优化双重处理程序（HNO ₃ -NH ₄ NO ₃），使用Cu-TEPA作为模板获得了Cu-SSZ-13催化剂，该催化剂在250到250的宽温度范围内显示90％以上的NOx转化率。即使在750和800℃水热老化后，GHSV仍为450℃，GHSV为〜400,000 h ^-1。XRD和H ₂ -TPR结果表明HNO ₃后处理可调节沸石的结晶度并优化Cu-SSZ-13催化剂中的铜种类分布。NH ₄ NO _3的进一步处理有效地降低了Cu / Al的比例，避免了在水热时效过程中Cu ²⁺离子的积累形成CuOx团簇。我们研究了Cu ²⁺对Cu-SSZ-13的水热稳定性的影响，发现了两个相反的作用。铜²⁺离子抑制SSZ-13沸石结构的脱铝，而过量的离子则容易积聚形成CuOx团簇，导致水热老化过程中沸石结构的长程有序塌陷。在沸石结构塌陷之前，由于保留了更多的活性Cu ^2+，具有高的Cu负载量的Cu-SSZ-13催化剂表现出更高的NH ₃ -SCR活性。但是，一旦沸石结构崩溃，Cu-SSZ-13催化剂在NH ₃ -SCR中就会完全失去脱硝活性。为了同时保证NOx还原活性和耐水热性，应通过HNO ₃和NH ₄仔细调整最佳Cu负载量（此处的Cu / Al = 0.22〜0.31）和原位合成Cu-SSZ-13的结构稳定性。NO ₃处理。