The high-temperature hydrothermal (HTH) stability is always a key factor that affects the NH₃-SCR performance and limits the industrial applications of Cu/SAPO-34. Herein, two Cu/SAPO-34 catalysts with different grain sizes are HTH aged to investigate the role of the grain size of Cu/SAPO-34 in holding the structure stability of catalysts and the relationships between the grain size and deNO_x performance over Cu/SAPO-34 during the HTH treatment. Characterization results illustrates that the relationship between the grain size and the stability of SAPO framework and the content of isolated Cu²⁺ ions. During the HTH treatment, CuO species more easily transfer to isolated Cu²⁺ species via migrating into the framework from the external surface of SAPO-34 for the larger-sized catalyst rather than the smaller-sized one. The re-distribution of Cu²⁺ in the larger-sized catalyst prevents Si-O(H)-Al from H₂O attacking during HTH treatment. Therefore, the larger-sized Cu/SAPO-34 maintains stronger structural stability and higher deNO_x activity than smaller-sized one after HTH treatment. This work provides a new strategy for design of high-temperature hydrothermal stabilized Cu/SAPO-34 for eliminating NO_x emitted from diesel engines.

高温水热（HTH）稳定性始终是影响NH ₃ -SCR性能并限制Cu / SAPO-34工业应用的关键因素。本文中，两个铜/ SAPO-34的催化剂具有不同的晶粒尺寸HTH老化研究在保持催化剂的结构稳定性和粒度和DENO之间的关系的Cu / SAPO-34的粒度的作用_X性能比铜在HTH治疗期间/ SAPO-34。表征结果表明，晶粒尺寸和SAPO骨架的稳定性与分离的Cu ²⁺离子含量之间的关系。在高温处理中，CuO物种更容易转移到分离的Cu ^2+中物种是通过从SAPO-34的外表面迁移到骨架中的，用于较大尺寸的催化剂，而不是较小尺寸的催化剂。Cu ²⁺在较大尺寸催化剂中的重新分布可防止HTH处理期间Si-O（H）-Al受到H ₂ O的侵蚀。因此，较大尺寸的Cu / SAPO-34保持更强的结构稳定性以及更高DENO _X比HTH处理后更小尺寸的一种活性。这项工作为高温水热稳定化的Cu / SAPO-34的设计提供了新的策略，以消除柴油机排放的NO _x。