Characterisation of CoIIand CoIIIin CoAPO molecular sieves
- 1 January 1991
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions
- Vol. 87 (6) , 891-895
- https://doi.org/10.1039/ft9918700891
Abstract
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 Brønsted and Lewis acid sites.Keywords
This publication has 1 reference indexed in Scilit:
- Aluminophosphate Molecular Sieves and the Periodic TableStudies in Surface Science and Catalysis, 1986