Selective electrochemical synthesis of ferrate on SnO₂-Sb₂O₃/Ti electrodes

The electrode of SnO₂-Sb₂O₃/Ti was manufactured in this research. The results prove that the electrochemical generation of FeO₄^2- could be carried out on this kind of electrode in a 14 mol/L NaOH solution without any impact of the side reaction of oxygen evolution reaction (OER) under the same experimental condition. The results indicate that the dissoluble ion, FeO₂^- is one of existent formations of Fe(III) compounds, the ion is a reactant of the chemical oxidation and electrochemical oxidation, the redox couple is not FeO₄^2-/Fe(OH)₃, but FeO₄^2-/FeO₂^- in the concentrated NaOH solution. The feebly amphoteric property of Fe (III) compounds plays a considerable role in the manufacture of safety rechargeable batteries. Furthermore, the onset potential value of electro-oxidation of FeO₂^-(0.38 V vs. Hg/HgO, 14 mol/L NaOH) is close to that of electro-reduction of FeO₄^2-(0.54 V) under the same research condition. The results also indicate that the mechanism of electrochemical generation of FeO₄^2- from FeO₂^- is an electrochemical mechanism. In addition, the excellent stability of the SnO₂-Sb₂O₃/Ti electrode was exhibited under the research condition.