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Structure and critical function of Fe and acid sites in Fe-ZSM-5 in propane oxidative dehydrogenation with N2O and N2O decomposition
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SYSNO ASEP 0420718 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Structure and critical function of Fe and acid sites in Fe-ZSM-5 in propane oxidative dehydrogenation with N2O and N2O decomposition Tvůrce(i) Sazama, Petr (UFCH-W) RID, ORCID
Sathu, Naveen Kumar (UFCH-W)
Tabor, Edyta (UFCH-W) RID, ORCID
Wichterlová, Blanka (UFCH-W) RID
Sklenák, Štěpán (UFCH-W) RID, ORCID, SAI
Sobalík, Zdeněk (UFCH-W) RIDZdroj.dok. Journal of Catalysis. - : Elsevier - ISSN 0021-9517
Roč. 299, MAR 2013 (2013), s. 188-203Poč.str. 16 s. Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova Fe-ZSM-5 zeolite ; Structure of Fe species ; Steamed Fe-zeolites Vědní obor RIV CF - Fyzikální chemie a teoretická chemie CEP GAP106/11/0624 GA ČR - Grantová agentura ČR GA203/09/1627 GA ČR - Grantová agentura ČR Institucionální podpora UFCH-W - RVO:61388955 UT WOS 000316774900020 EID SCOPUS 84873618740 DOI 10.1016/j.jcat.2012.12.010 Anotace The structure and population of ion-exchanged Fe ions, Fe-oxo species, and Fe-oxo oligomers and Fe2O3 oxide particles and the concentration of acid sites in non-steamed and steamed Fe-ZSM-5 were elucidated using semi-quantitative Mossbauer and FTIR analysis supplemented by UV-Vis and H-2-TPR. Differences in the concentration of the individual Fe species and acid sites were related to the activity and time-on-stream behavior of Fe-zeolites in decomposition of N2O and oxidative dehydrogenation of propane to propene with N2O. The evacuated non-steamed FeH-ZSM-5 contained high concentration of Bronsted sites and predominantly bare Fe(II) ions (72%), and less mono- and dinuclear Fe(III) (16-19%) and oligomeric Fe(III)-oxo species (9-12%). The steamed Fe(H)-ZSM-5st zeolites were greatly reorganized, resulting in a low concentration of both the Bronsted sites and bare Fe(II) ions, and the T-d-coordinated Fe( III) ions in the Fe-Al-Si extra-framework species (43-47%) and Fe-oxide-like particles (30-33%) prevailed. The redox state of Fe in both non-steamed and steamed Fe-ZSM-5 was strongly influenced by the reaction conditions of N2O decomposition and C3H8/N2O. Bare counter Fe ions balanced by Al-Si-Si-Al sequences in 6MRs of the framework undergo reversible redox Fe(III)O-/Fe(II) cycle during N2O/evacuation treatments and represent the most active site in the decomposition of N2O to molecular components. In contrast, both mono-, dinuclear Fe(III)-oxo and Fe(III)-oxo oligomers are reduced by propane to Fe(II) at conditions of the C3H8/N2O reaction. The reduced Fe(II) species with N2O form Fe(III)-O- and facilitate transfer of atomic oxygen to propane with formation of propanol dehydrated to propene. Thus, all dispersed Fe species represent highly active sites in oxidative dehydrogenation of propane to propene with N2O. Pracoviště Ústav fyzikální chemie J.Heyrovského Kontakt Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Rok sběru 2014
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