Repozytorium Uniwersytetu Jagiellońskiego

Quantitative IR studies of the concentration of different nickel sites in NiZSM-5 zeolites

Quantitative IR studies of the concentration of ...

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dc.contributor.author Góra-Marek, Kinga [SAP11018751] pl
dc.contributor.author Glanowska, Anna pl
dc.contributor.author Datka, Jerzy [SAP11003748] pl
dc.date.accessioned 2015-08-21T10:31:39Z
dc.date.available 2015-08-21T10:31:39Z
dc.date.issued 2012 pl
dc.identifier.issn 1387-1811 pl
dc.identifier.uri http://ruj.uj.edu.pl/xmlui/handle/item/14819
dc.language eng pl
dc.title Quantitative IR studies of the concentration of different nickel sites in NiZSM-5 zeolites pl
dc.type JournalArticle pl
dc.description.physical 162-169 pl
dc.abstract.en Quantitative IR studies were realized in order to determine the concentration of Ni 2+ and Ni + in two zeo- lites NiZSM-5 differing in Si/Al and nickel content. The NiZSM-5 zeolite of Si/Al = 11.5 contained most of Ni 2+ in exchange positions whereas another one, of Si/Al = 40 contained most of Ni 2+ in the form of oxides. Also the Ni + ions in NiZSM-5 reduced by CO were investigated. The experimental procedure of quantita- tive studies was elaborated and the condition of stoichiometric reaction between probe molecule (CO or NO) and sorption site (Ni 2+ or Ni + ) was fulfilled: each CO or NO molecule introduced into the IR cell reacted with one Ni 2+ forming Ni 2+ (CO) or Ni 2+ (NO) adducts. The procedure was also elaborated for quan- titative studies of concentration of Ni + in zeolite reduced. The absorption coefficients of IR bands of Ni 2+ (CO), Ni 2+ (NO) and Ni + (CO) at 2212, 1898, and 2109 cm 1 , respectively were determined, and finally the concentrations of Ni 2+ and Ni + were calculated. In the zeolite of Si/Al = 11.5 the concentration of Ni 2+ in exchange positions determined by our IR studies was nearly the same as that determined by chemical analysis. The values of the absorption coefficients turned out to be independent on the probe molecule (CO or NO). In the zeolite of Si/Al = 40, containing the most of Ni 2+ in the form of oxides, the concentration of Ni 2+ found by IR was 66% of concentration of Ni determined by chemical analysis demonstrating that dispersion of Ni 2+ was low and some of Ni 2+ was hidden inside oxide clusters being inaccessible to probe molecules. In reduced NiZSM-5 of Si/Al = 11.5 and 40 the concentration of Ni + determined by IR studies was nearly the same as concentration of Ni determined by chemical analysis. In NiZSM-5 of Si/Al = 40 the dispersion of Ni increased distinctly upon the reduction, and all Ni + cations became accessible to probe molecules or reactants. pl
dc.subject.en carbon monoxide pl
dc.subject.en ZSM-5 pl
dc.subject.en nitrogen monoxide pl
dc.subject.en quantitative IR studies pl
dc.description.volume 158 pl
dc.description.points 35 pl
dc.identifier.doi 10.1016/j.micromeso.2012.03.027 pl
dc.identifier.eissn 1873-3093 pl
dc.title.journal Microporous and Mesoporous Materials pl
dc.language.container eng pl
dc.affiliation Wydział Chemii : Zakład Chemii Nieorganicznej pl
dc.subtype Article pl
dc.rights.original bez licencji pl
.pointsMNiSW [2012 A]: 35


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