Publisher: Elsevier BV

Issue:

License: https://www.elsevier.com/tdm/userlicense/1.0/

Publication date(s): 2019/01 (print)

Pages: 283-291

Volume: 570 Issue:

Journal: Applied Catalysis A: General

Link: https://api.elsevier.com/content/article/PII:S0926860X18305817?httpAccept=text/xml

URL: http://dx.doi.org/10.1016/j.apcata.2018.11.026

Fe-containing zeolites were studied as catalysts for the standard NH₃-SCR reaction with the primary aim of gaining insight into the structure-function relationship of these materials. Catalysts with different Fe nuclearity (i.e. isolated species, clusters, large particles) were synthesised by incipient wetness impregnation, using H-ZSM-5, H-SSZ-13 and Silicalite-1 as supports, and characterised by in situ and operando X-ray emission spectroscopy (XES) and high energy resolution fluorescence detected X-ray absorption near-edge spectroscopy (HERFD-XANES) under NH₃-SCR conditions. The combination of these techniques allowed us to obtain a detailed understanding of the changes in Fe coordination, oxidation state and geometry occurring during reaction. The results obtained suggested that isolated octahedral Fe³⁺ species on H-ZSM-5 are highly active under the conditions studied, undergoing reduction when exposed to NH₃ or under SCR conditions. In contrast, isolated tetrahedral Fe³⁺ sites present in Silicalite-1 exhibited lower redox properties, leading to a reduced NO conversion. Clusters and Fe_xO_y particles on H-SSZ-13 exhibited low SCR activity.