The electrochemical oxidation : A new way for preparing highly oxidized ferrites
Langue
en
Article de revue
Ce document a été publié dans
Journal de Physique IV Proceedings. 1997, vol. 07, n° C1, p. 49-52
EDP Sciences
Résumé en anglais
The electrochemical oxidation is depicted as a novel and powerful route for preparing highly oxidized ferrites. The reaction is achieved at room temperature, in air, in alkaline solution (1M KOH or NaOH). This process has ...Lire la suite >
The electrochemical oxidation is depicted as a novel and powerful route for preparing highly oxidized ferrites. The reaction is achieved at room temperature, in air, in alkaline solution (1M KOH or NaOH). This process has been used for preparing various new compounds and especially perovskite-type ferrites such as SrMO3 ( M = Fe or/and Co ) or Sr2LaFe3O9-ε. The characterization of the samples shows that they remain well crystallized after the electrochemical treatment and bulky oxidized. The reaction can be described as an intercalation process of oxygen atoms into the host lattice of the starting material. For instance, the chemical analysis as well as Mössbauer spectroscopy data of SrFeO3 or of Sr2FeCoO6 reveal iron cations to be exclusively tetravalent. On the other hand, Sr2LaFe3O9-ε exhibits at decreasing temperature a disproportionation of the mixed valence of iron. Potentiostatic and galvanostatic experiments have shown that the amount of intercalated oxygen can be controlled and that the process is reversible. A mechanism involving the formation of O- species that can diffuse inside the bulk of the material, is proposed.< Réduire
Origine
Importé de halUnités de recherche