金属负载型分子筛催化剂在NH3-SCR反应中水热稳定性的研究进展

NO_x控制是目前大气污染控制领域的重要研究内容，NH₃选择性催化还原技术（NH₃-SCR）是消除NO_x最有效的技术之一，其核心是高性能催化剂的开发。本研究综述了金属负载型分子筛催化剂（Cu基和Fe基分子筛催化剂）的NH₃-SCR活性、水热稳定性以及水热老化失活机制，并对影响催化剂水热稳定性的因素（包括Si/Al比、分子筛拓扑结构、活性金属负载量、粒径和合成方法等）进行了系统阐述，总结了一些有效提高催化剂水热稳定性的改性方法，比如磷改性、第二活性金属改性、碱金属改性和外表面改性等。最后，对进一步提高金属负载型分子筛催化剂在NH₃-SCR反应中的水热稳定性进行了展望。

Research progress of hydrothermal stability of metal-based zeolite catalysts in NH3-SCR reaction

Emission of NO_x from stationary and mobile sources had caused many environmental problems. NH₃ selective catalytic reduction technology (NH₃-SCR) is one of the most effective technologies to eliminate NO_x based on developing high-efficient catalysts. In this review, the catalytic activity for NH₃-SCR, hydrothermal stability and deactivation mechanism of metal-based zeolite catalysts (mainly Cu- and Fe-based zeolite catalysts) employed in NH₃-SCR were summarized. The main factors affecting the hydrothermal stability of Cu- or Fe-based zeolite catalysts in NH₃-SCR, such as Si/Al ratio, zeolite topological structure, metal content, particle size and preparation methods of catalysts, were systematically reviewed. The modification approaches addressed in recent researches which could effectively improve the hydrothermal stability of metal-based zeolites in NH₃-SCR, such as element modification using phosphorus, second active metal, alkali (earth) metal, and surface modification, were discussed. Hopefully, this review could provide a fundamental understanding of the deactivation behaviors of Cu- and Fe-based zeolite catalysts and pave the way towards the improvement of hydrothermal stability of zeolite catalysts in NH₃-SCR.