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

Achieving high catalytic activity and maintaining low -temperature hydrothermal durability are essential for applying Cu-SAPO-34 catalyst to eliminate NO x 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 NH 3 -SCR. Among them, Cu-SAPO-34(MA) has more amount of strong acid site and isolated Cu 2+ 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 NO x 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.