Effect of various templates-assisted Cu ion incorporation into SAPO-34 on low-temperature hydrothermal durability for NH3-SCR reaction

• Published in: Fuel (Guildford) 2024-08, Vol.369, p.131717, Article 131717
• Main Authors: Hou, Jia, Zhong, Chengming, Yin, Chengyang, Wang, Ruidan, Wang, Lanyi, Ke, Ming, Zhao, Zhen
• Format: Article
• Language: English
• Subjects: Cu-SAPO-34; In situ DRIFTS; Low-temperature hydrothermal durability; NH3-SCR; template-assisted ion incorporation (TII); Various SDAs
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2024.131717

[Display omitted] •Cu-SAPO-34 catalysts were prepared by various templates-assisted ion incorporation method.•Cu-SAPO-34(MA) performed excellent NH3-SCR activity and low temperature hydrothermal durability.•The main reasons of catalysts deactivation after low temperature hydrothermal treatment were put forward.•Low temperature hydrothermal aging hinders the L-H pathway on Cu-SAPO-34(PA) and decreases the NOx conversion. Achieving high catalytic activity and maintaining low-temperature hydrothermal durability are essential for applying Cu-SAPO-34 catalyst to eliminate NOx from diesel vehicles. Cu-SAPO-34 were obtained by straightforward template-assisted ion incorporation (TII) method using morpholine (MA), propylamine (PA), and diethylamine (DEA) as structure directing agents (SDAs). Various SDAs can influence the structure and physicochemical properties of catalysts synthesized by TII method, thus affect the activity and low temperature moisture durability during NH3-SCR. Among them, Cu-SAPO-34(MA) has more amount of strong acid site and isolated Cu2+ ions, showing higher catalytic activity and better low temperature moisture durability. Therefore, MA is better suited for TII method in synthesizing Cu-SAPO-34 for NOx elimination. In situ DRIFTS results imply that Cu-MA and Cu-DEA primarily obey Langmuir–Hinshelwood (L-H) pathway before and after aging. However, moisture treatment impedes the Langmuir–Hinshelwood mechanism on Cu-PA catalyst, which instead primarily follows the Eley–Rideal mechanism.