ISSN:
1572-879X
Keywords:
Fe/ZSM‐5
;
steam treatment
;
deactivation
;
hydrothermal stability
;
SCR
;
de‐NOx
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The stability of Fe/ZSM‐5 de‐NOx catalyst has been investigated. The samples are prepared by sublimation of iron chloride. Substantial amount of protons are found to remain in the fresh catalyst after washing and calcination. After 10 h exposure to wet exhaust gas at 600°C, the catalyst is severely deactivated. The presence of steam induces dealumination of the ZSM‐5 matrix, because the protons provide the point of attack by water. In addition, highly reactive distorted tetrahedral iron species and tetrahedral species change to less reactive octahedral iron ions or iron agglomerates upon aging treatment. With the second sublimation of iron chloride, the iron loading is increased and thus the concentration of remaining protons is reduced. Also, the catalyst turns out to preserve more reactive iron ions after aging treatment. In conclusion, the second sublimation is believed to bring about a remarkable improvement in the stability of the Fe/ZSM‐5 catalyst although its de‐NOx activity is slightly decreased.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1019044032219
