Selective catalytic reduction of NOx by NH3 over Cu-AEI zeolite catalyst: Current status and future perspectives

Cu-exchanged small-pore SSZ-39 and SAPO-18 (Cu-AEI) zeolite catalysts have attracted more and more attention due to the high NH3-SCR performance and remarkable hydrothermal stability, which are crucial for the control of NOx from the diesel exhaust. This paper comprehensively reviews the research progress on Cu-AEI zeolites for NH3-SCR of NOx, encompassing the NH3-SCR reaction mechanism, hydrothermal aging mechanism, chemical poisoning mechanism, multi-route synthesis method, and performance optimization method. Our objective is to provide a fundamental understanding of the NH3-SCR reaction over Cu-AEI zeolite catalysts and highlight the relationship between the structure and the catalytic performance, which would shed light on the design of more highly active and durable Cu-AEI zeolite catalyst for the NH3-SCR of NOx. Finally, the challenges and prospects for Cu-exchanged small-pore zeolites have been proposed, which would promote the practical application of these catalysts to meet the strict emission regulations in the future.