Abstract:

This paper provides an overview of the current state of the art of SSZ-39 zeolite synthesis technology, with a focus on the progress of modified sieves in NH₃ selective catalytic reduction(NH₃-SCR) for diesel vehicle exhaust treatment. The synthesis strategy, NH₃-SCR catalytic mechanism, hydrothermal stability of the catalyst, and anti-deactivation performance are discussed comprehensively from various perspectives. Various synthetic routes of SSZ-39 zeolite are examined in detail, including trans-crystallization, direct hydrothermal synthesis, solvent-free method, and crystal species-assisted synthesis. The advantages and disadvantages of these methods are objectively evaluated. Furthermore, this paper summarizes recent research progress on the active sites [Cu(OH)]⁺ and Cu²⁺ of Cu-SSZ-39 catalysts and analyzes in depth their intrinsic mechanisms of deactivation due to hydrothermal aging, phosphorus poisoning, alkaline earth metal poisoning etc., which reveals the close correlation between sieve structure and catalytic performance. In order to enhance the catalytic performance, precise regulation of active sites through specific metal doping and innovative preparation methods is proposed. However, current studies mainly focus on the effect of single toxic substance on the catalyst performance, therefore further investigation of the anti-poisoning deactivation strategies for coexisting toxic substances under real operating conditions is needed. Although some progress has been made in studying deactivation mechanisms, key issues such as improving sulfur resistance and alkali metal resistance have not yet been fully addressed effectively. Future research needs to manage breakthroughs in these areas to promote wider application of SSZ-39 zeolite in diesel vehicle exhaust treatment.

Key words: SSZ-39 zeolite, synthesis, selective catalytic reduction (SCR), deactivation, hydrothermal stability

摘要：

概述了SSZ-39分子筛的合成技术现状，特别是改性后在柴油车尾气处理氨气选择性催化还原（NH₃-SCR）反应中的应用研究进展。从合成策略、NH₃-SCR催化机制、催化剂的水热稳定性及抗失活性能等多个角度进行了深入探讨。详细梳理了SSZ-39分子筛的多种合成途径，包括转晶法、直接水热合成法、无溶剂法以及晶种辅助合成法等，并对这些方法的优劣进行了客观评价。此外，本文还总结了近年来关于Cu-SSZ-39催化剂活性位点[Cu(OH)]⁺及Cu²⁺的研究进展，深入剖析了水热老化、磷中毒、碱土金属中毒等因素导致其失活的内在机制，进一步揭示了分子筛结构与催化性能之间的紧密关联。为了提升催化剂性能，本文提出了通过选择特定金属掺杂和创新性的制备方法来实现对活性位点的精准调控。然而，当前研究主要聚焦于单一有毒物质对催化剂性能的影响，对真实工况下多种有毒物质共存时催化剂抗中毒失活策略尚需深入研究。尽管对失活机理的研究已取得一定进展，但如何提高催化剂的抗硫性能、耐碱金属性能等关键问题仍未能得到全面有效的解决。未来仍需进一步探索这些领域，以推动SSZ-39分子筛在柴油车尾气处理领域的广泛应用。

关键词: SSZ-39分子筛, 合成, 选择性催化还原, 失活, 水热稳定性