The electrochemical properties of SrFeO2.91 dispersed on a high area carbon in alkaline media have been investigated by cyclic voltammetry and in situ Mosbauer spectroscopy. The results provide evidence that a fraction of Fe(IV) sites, as monitored in situ, undergo a gradual and irreversible decrease upon exposure of the material to an alkaline solution. This has been attributed to the reduction of such oxidized sites by water, generating most likely an hydroxylated ferric species. In addition it was found that the voltammetry peak observed during the first scan in the negative direction is associated with the irreversible destruction of the perovskite lattice. The only iron species formed and detected by Mossbauer spectroscopy is Fe(OH)2 which then urdergoes reoxidation at much more positive potentials to yield a hydrated ferric oxyhydroxide.
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