10-O-04 - Site selective adsorption and catalytic properties of iron in FER and BEA zeolites

Sobalı́k, Zdenĕk; Šponer, Judit E.; Tvarůžková, Z.; Vondrová, Alena; Kuriyavar, Satish I.; Wichterlová, Blanka

doi:10.1016/s0167-2991(01)81204-0

Cited by 19 publications

(19 citation statements)

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“…Together with framework (FW) iron sites in tetrahedral coordination, iron species in extra-framework (EFW) position are present and it is generally accepted that the latter species are those active in benzene hydroxylation with N 2 O. However, different type of EFW iron species were evidenced to be present in Fe/MFI catalysts: (i) isolated Fe III ions in different locations in the zeolite cages (indicated as a, b and g positions [12]), (ii) isolated Fe II ions [10], (iii) binuclear complexes [8], and (iv) iron-oxide nanoparticles [13]. Recently, it was also indicated that nano-oxide clusters of random structure (''ferrihydrate'') are active in phenol synthesis, but these species transform to magnetite (partially active) or hematite (inactive) iron-oxide particles [14].…”

Section: Introductionmentioning

confidence: 99%

Performances of Fe-[Al, B]MFI catalysts in benzene hydroxylation with N2O

et al. 2005

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Section: Introductionmentioning

confidence: 99%

Performances of Fe-[Al, B]MFI catalysts in benzene hydroxylation with N2O

et al. 2005

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“…The iron content is 0.98 wt%, i.e., the Fe/Al ratio equals 0.12. Our previous studies have shown that most of the iron at this relatively low iron loading is located in cationic sites, predominantly in b positions [10] and the formation of iron-oxidic species is suppressed [11].…”

Section: Fe-ferrieritementioning

confidence: 84%

N2O Decomposition over Fe-Ferrierite: Primary and Secondary Reactions with Reducing Agents

Nováková

Sobalı́k

2008

Catal Lett

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The decomposition of N 2 O either alone or with several reducing agents (CH 4 , CO, NO and D 2 ) was followed by temperature-programmed desorption of surface species formed during the reactions. TPD products formed in these ''primary'' reactions were compared with the TPD products after ''secondary'' reactions of the same set of reducing agents with the surface species formed during the primary reactions. Changes in TPD products after reactions measured under various conditions were analyzed in detail. These experiments provided a background for studies of the nature and reactivity of surface species formed during N 2 O reactions over Fe-ferrierite. The relevance of these experimental results to the mechanism of the N 2 O elimination is discussed.

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“…These vibrations are in the range of 920-980 cm À1 and depend on the coordinated metal ion, which is close to available experimental values. 57,58 The structure and relative stability of different Zn-containing cationic species in ZSM-5 zeolite: Zn 2þ , ZnOH þ , Zn(H 2 O) 2þ and ZnOZn 2þ , were studied both with isolated and embedded (covEPE) clusters. The model zeolite fragments represented one and two five-membered rings, M5 and M7, respectively.…”

Section: Extra-framework Metal Ions and Their Complexesmentioning

confidence: 99%