Characterisation of CoIIand CoIIIin CoAPO molecular sieves

Autor:	Bettina Kraushaar-Czarnetzki, Ronald René Andréa, C. A. Emeis, W.H.J. Stork, Wilma G. M. Hoogervorst
Rok vydání:	1991
Předmět:	chemistry.chemical_compound Adsorption Chemistry Inorganic chemistry Pyridine chemistry.chemical_element Infrared spectroscopy Lewis acids and bases Physical and Theoretical Chemistry Molecular sieve Spectroscopy Cobalt Redox
Zdroj:	J. Chem. Soc., Faraday Trans.. 87:891-895
ISSN:	1364-5455 0956-5000
DOI:	10.1039/ft9918700891
Popis:	CoAPO molecular sieves of the structure types 5, 11, 16 and 34 have been investigated by means of electron absorption spectroscopy, temperature-programmed reduction and infrared spectroscopy in combination with pyridine adsorption, the purpose being to determine the amounts of framework and non-framework cobalt and to study the properties of incorporated cobalt with respect to stability, redox behaviour and associated acidic properties. It has been shown that framework and non-framework cobalt species exhibit different spectroscopic properties and can be distinguished from each other. The framework cobalt acceptance and the stability of the different structures decrease in the order CoAPO4-5 > CoAPO4-11 > CoAPO4-16 > CoAPO4-34. In stable structures such as 5 and 11, framework cobalt can perform reversible redox reactions CoII⇌ CoIII, which are accompanied by changes in the concentration of Bronsted and Lewis acid sites.
Databáze:	OpenAIRE
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