Lin Jinhan, Hu Xueyang, Tan Xuechao, Lin Chunxi, Zhang Yan, Shan Wenpo, He Hong
Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Science, Xiamen 361021, China.
Zhejiang Key Laboratory of Pollution Control for Port-Petrochemical Industry, Ningbo Urban Environment Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Ningbo 315800, China.
Environ Sci Technol. 2025 Jul 29;59(29):15515-15525. doi: 10.1021/acs.est.5c05828. Epub 2025 Jun 30.
Copper-exchanged SSZ-39 zeolite catalysts have been proven to be more hydrothermally stable than Cu-SSZ-13 catalysts. However, the synthesis of high-silica SSZ-39 zeolites is still a significant challenge. The excess framework Al in Cu-exchanged Al-rich SSZ-39 catalysts leads to not only severe dealumination during hydrothermal aging but also damage to the SCR-active Cu ions by the detached Al. In this work, in-depth knowledge of the stabilization of Al by Y is provided. It was found that the energy needed to break the first Al-O bond is significantly enhanced due to the Y located in the eight-membered rings. Additionally, Cu-2Z and Y have a synergistic effect on the stabilization of the framework Al. The introduction of Y into the Cu-SSZ-39 catalyst with hydrothermally stable Cu-2Z as the only Cu species remarkably enhanced both the low-temperature activity and the hydrothermal stability. The catalyst maintained excellent deNO activity even after hydrothermal aging at the extremely high temperature of 940 °C. Both stable Cu species and stable framework Al are essential for the design of hydrothermally stable Cu-exchanged zeolite catalysts.
铜交换的SSZ-39沸石催化剂已被证明比Cu-SSZ-13催化剂具有更高的水热稳定性。然而，高硅SSZ-39沸石的合成仍然是一个重大挑战。富含铝的铜交换SSZ-39催化剂中过量的骨架铝不仅会导致水热老化过程中的严重脱铝，还会使脱离的铝对SCR活性铜离子造成损害。在这项工作中，深入了解了Y对铝的稳定作用。研究发现，由于Y位于八元环中，打破第一个Al-O键所需的能量显著提高。此外，Cu-2Z和Y对骨架铝的稳定具有协同作用。以水热稳定的Cu-2Z作为唯一的铜物种引入Y到Cu-SSZ-39催化剂中，显著提高了低温活性和水热稳定性。即使在940℃的极高温度下水热老化后，该催化剂仍保持优异的脱硝活性。稳定的铜物种和稳定的骨架铝对于设计水热稳定的铜交换沸石催化剂都是必不可少的。
