Siting and Distribution of the Co Ions in Beta Zeolite: A UV-Vis-NIR and FTIR Study

0181428 - UFCH-W 20020094 RIV US eng J - Journal Article
Dědeček, Jiří - Čapek, Libor - Kaucký, Dalibor - Sobalík, Zdeněk - Wichterlová, Blanka
Siting and Distribution of the Co Ions in Beta Zeolite: A UV-Vis-NIR and FTIR Study.
Journal of Catalysis. Roč. 211, č. 1 (2002), s. 198-207. ISSN 0021-9517. E-ISSN 1090-2694
R&D Projects: GA MŠMT OC D15.20; GA ČR GA104/00/0640
Institutional research plan: CEZ:AV0Z4040901
Keywords : Co-beta * Co(II) ions * cation siting
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 3.118, year: 2002

The Co(II) ion sites in dehydrated Beta zeolites, consisting of polymorphs A, B and C, were identified using an approach based on a similarity between Vis spectra of the Co(II) ions in mordenite, ferrierite ZSM-5 and beta zeolites, and similarity in local framework structures accommodating the Co(II) ions in these zeolites. The results were supported by FTIR spectra in the region of skeletal vibrations showing the characteristic shifts of framework T-O-T vibrations induced by the framework perturbations due to the Co(II) ions at cationic sites. Three different cationic sites accommodating divalent metal ions in Beta zeolite were found. Their positions in the channel system and local framework arrangements in different polymorphs of Beta zeolites were suggested. The .alfa. site is formed in polymorph C of the Beta structure by an elongated six-member ring composed of two folded connected five-member rings. The Co(II) ions at the .alfa. site exhibit an absorption band.
Permanent Link: http://hdl.handle.net/11104/0078000