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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
Bibliographic description
| title: | The reduction and oxidation of Co species in CoZSM-5 zeolites studied by IR spectroscopy |
| author: | Góra-Marek Kinga 
|
| journal title: | Topics in Catalysis |
| title of volume: | Catalysis for society |
| volume: | 52 |
| issue: | 8 |
| date of publication : | 2009 |
| pages: | 1023-1029 |
| ISSN: |
1022-5528 |
| eISSN: |
1572-9028 |
| DOI: | |
| language: | English |
| journal language: | English |
| abstract in English: | 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). |
| keywords in English: | CoZSM-5 zeolite, reduction, oxidation, IR spectroscopy |
| affiliation: | Wydział Chemii : Zakład Chemii Nieorganicznej |
| type: | journal article |
| subtype: | academic paper |
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Projekt „Repozytorium otwartego dostępu do dorobku naukowego i dydaktycznego UJ” współfinansowany w ramach poddziałania 2.3.1 „Cyfrowe udostępnianie zasobów nauki” Programu Operacyjnego Polska Cyfrowa z Europejskiego Funduszu Rozwoju Regionalnego i budżetu państwa na podstawie umowy o dofinansowanie nr POPC.02.03.01-00-0030/17-00
