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The reduction and oxidation of Co species in CoZSM-5 zeolites studied by IR spectroscopy

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The reduction and oxidation of Co species in CoZSM-5 zeolites studied by IR spectroscopy

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dc.contributor.author Góra-Marek, Kinga [SAP11018751] pl
dc.date.accessioned 2015-09-25T12:26:34Z
dc.date.available 2015-09-25T12:26:34Z
dc.date.issued 2009 pl
dc.identifier.issn 1022-5528 pl
dc.identifier.uri http://ruj.uj.edu.pl/xmlui/handle/item/15798
dc.language eng pl
dc.title The reduction and oxidation of Co species in CoZSM-5 zeolites studied by IR spectroscopy pl
dc.type JournalArticle pl
dc.description.physical 1023-1029 pl
dc.abstract.en The process of reducing Co ions in zeolite CoZSM-5 by NO, H2 and CO, as well as of oxidizing them by O2 was studied by IR spectroscopy with CO as the probe molecule for Co2+ and NO as the probe for Co3+. Two zeolites of different Co status were used: in the first, Co2+ ions were localized mostly in cation exchange positions, and in the second most of the Co2+ occurred in the form of CoO and oxide-like clusters. IR studies evidenced that NO reduced some Co3+ to Co2+ already at room temperature, and also reduced some Co2+ to lower oxidation states (probably Co+) at 670 and 1070 K. Only Co2+ in exchange positions could be reduced with NO. The treatment of zeolite CoZSM-5 with H2 or with CO at 670 and 1070 K made the reduction of Co3+ to Co2+ (the contribution of Co3+ decreased and the contribution of Co2+ increased). IR studies illustrated that the most electron-acceptor Co3+ (characterized by a high frequency Co3+–NO band) were transformed, by reduction, into the most electron-acceptor Co2+ (characterized by a high frequency Co2+–CO band). The treatment of zeolite CoZSM-5 with oxygen at 670–1070 K resulted in the oxidation of Co2+ to Co3+ (the contribution of Co2+ decreased while the contribution of Co3+ increased). pl
dc.subject.en CoZSM-5 zeolite pl
dc.subject.en reduction pl
dc.subject.en oxidation pl
dc.subject.en IR spectroscopy pl
dc.description.volume 52 pl
dc.description.number 8 pl
dc.identifier.doi 10.1007/s11244-009-9260-y pl
dc.identifier.eissn 1572-9028 pl
dc.title.journal Topics in Catalysis pl
dc.title.volume Catalysis for society pl
dc.language.container eng pl
dc.affiliation Wydział Chemii : Zakład Chemii Nieorganicznej pl
dc.subtype Article pl


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