Kinetic Aspects of Ion Exchange in KhFek[Fe(CN)6]l·mH2O Compounds: A Combined E

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• 作者：D. Gim&eacute ; nez-Romero ; P. R. Bueno ; C. Gabrielli ; J. J. Garcí ; a-Jareñ ; o ; H. Perrot ; F. Vicente
• 刊名：Journal of Physical Chemistry B
• 出版年：2006
• 出版时间：October 5, 2006
• 年：2006
• 卷：110
• 期：39
• 页码：19352 - 19363
• 全文大小：187K
• 年卷期：v.110,no.39(October 5, 2006)
• ISSN：1520-5207

文摘

The present paper quantifies and develops the kinetic aspects involved in the mechanism of interplay betweenelectron and ions presented elsewhere¹ for K_hFe_k[Fe(CN)₆]_l·mH₂O (Prussian Blue) host materials. Accordingly,there are three different electrochemical processes involved in the PB host materials: H₃O⁺, K⁺, and H⁺insertion/extraction mechanisms which here were fully kinetically studied by means of the use of combinedelectronic and mass transfer functions as a tool to separate all the processes. The use of combined electronicand mass transfer functions was very important to validate and confirm the proposed mechanism. Thismechanism allows the electrochemical and chemical processes involved in the K_hFe_k[Fe(CN)₆]_l·mH₂O hostand Prussian Blue derivatives to be understood. In addition, a formalism was also developed to considersuperficial oxygen reduction. From the analysis of the kinetic processes involved in the model, it was possibleto demonstrate that the processes associated with K⁺ and H⁺ exchanges are reversible whereas the H₃O⁺insertion process was shown not to present a reversible pattern. This irreversible pattern is very peculiar andwas shown to be related to the catalytic proton reduction reaction. Furthermore, from the model, it was possibleto calculate the number density of available sites for each intercalation/deintercalation processes and inferthat they are very similar for K⁺ and H⁺. Hence, the high prominence of the K⁺ exchange observed in thevoltammetric responses has a kinetic origin and is not related to the amount of sites available for intercalation/deintercalation of the ions.