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Electrochemical production of iron-containing composites based on metal ferrites

Ya.A.Vissurkhanova

 The paper presents the results of an investigation into the electrochemical reduction of metal ferrites with the formation of iron-containing composites and their electrocatalytic activity in the electrohydrogenation of organic compounds. Samples of metal ferrites (CuFe2O4, NiFe2O4 and ZnFe2O4) were prepared by co-precipitation method without and with addition of polyvinyl alcohol as polymer stabilizer. The obtained samples were annealed at 500º?, 700º? and 900º? for 2 hours in corundum crucibles with a closed lid. Their structural-phase changes and morphological features have been studied by XRD analysis and electron microscopy. It was found that all copper ferrite samples prepared without and in the presence of polymer are able to be reduced in electrochemical system on Cu-cathode in aqueous-alkaline catholyte at 30ºC with the formation of Cu0- and Fe0-containing composites with metal predominance depending on the annealing temperature. NiFe2O4 and ZnFe2O4 ferrite samples undergo electrochemical reduction only in the case of their synthesis in polymer solutions; the phase constitutions of resulting composites are also depended on the annealing temperature. Thus, it has been established that the content of both metals in the composites formed after reduction can be controlled, and that can be used in the additional selective extraction of these metals from their ferrites in metallurgical wastes. The resulting composites with reduced metal particles were used as electrocatalysts in electrohydrogenation of organic compounds. The high electrocatalytic activity of the CuFe2O4-based composites in acetophenone electrohydrogenation and low one for NiFe2O4-based composites were found, which is due to the structure of Fe-Ni particles formed.