Rapid synthesis of Cu-SSZ-39 and study of phosphorus poisoning in NH3-SCR

Abstract

Cu-SSZ-39 has attracted great interest due to its excellent NH3-SCR activity and hydrothermal stability. However, impediments such as high synthesis costs, lengthy preparation duration, and the issue of phosphorus-induced deactivation have hampered its widespread commercialization. Herein, H2O2 was first introduced into the synthesis system dedicated to the rapid synthesis of SSZ-39, and the crystallization time was shortened to 3 d. Various characterization techniques were used to analyze deeply the structure–activity relationship of the resulting Cu-SSZ-39 catalysts before and after phosphorus poisoning. Our findings revealed a pronounced decline in acidic sites and active copper species as Cu-SSZ-39 underwent deeper phosphorus poisoning, leading to the formation of Cu-P species and a consequential reduction in the low-temperature activity of the catalyst. Surprisingly, hydrothermal treatment of the poisoned catalyst allowed the decomposition of Cu-P species to generate active Cu2+ species, alleviating the poisoning effect. It was also shown that phosphorus poisoning did not affect the low-temperature reaction mechanism of Cu-SSZ-39, which still followed the “L-H” reaction pathway. Finally, it was unexpectedly found that the anti-phosphorus poisoning performance of 0.9C-Cu-SSZ-39 significantly improved after mesopores were introduced.