Abstrakti
Cu-SSZ-13 is a highly active catalyst to remove NO x in the emission of diesel-powered engine. However, the enhancement of its stability in high-temperature (HT) hydrothermal conditions is a well-known challenge in application. This work presents a simple strategy to significantly improve its hydrothermal stability under HT hydrothermal condition by mechanically mixing another CHA type zeolite, Cu-SAPO-34. Both the two zeolites are synthesized via one-pot method, mixed in different ratios, and treated in 10% H 2 O/air at 750 °C for 16 h. The mixed samples are characterized before and after the hydrothermal treatment, and tested in NH 3 -SCR from 150 to 550 °C. The results show the activity of the hydrothermally treated catalysts increases with the increase of the amount of Cu-SAPO-34 up to 50 wt% in the mixed sample. The hydrothermal stability of Cu-SSZ-13 is obviously enhanced by mixing with Cu-SAPO-34. The dealumination is suppressed during the hydrothermal treatment; the framework and the isolated Cu 2+ sites are largely maintained in Cu-SSZ-13. This is attributed to the interaction between the two CHA zeolites during the hydrothermal treatment. We propose the delivery of extra-framework P species from Cu-SAPO-34 to Cu-SSZ-13 is critical to enhance the HT hydrothermal stability.
Alkuperäiskieli | Englanti |
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Sivut | 627-634 |
Julkaisu | Catalysis Today |
Vuosikerta | 355 |
Numero | Special issue |
Varhainen verkossa julkaisun päivämäärä | 30 maaliskuuta 2019 |
DOI - pysyväislinkit | |
Tila | Julkaistu - 15 syyskuuta 2020 |
OKM-julkaisutyyppi | A2 Arvio tiedejulkaisuussa (artikkeli) |