A. Hicklinga and D.J.G. Ives
aDonnan Laboratories, Liverpool University, England
Received 5 June 1974;
revised 10 July 1974.
Available online 21 November 2001.
Abstract
The cathodic reduction of Fe2O3, FeOOH, and Fe3O4 in dilute sulphuric acid has been directly investigated using graphite paste electrodes containing the oxides. It has been found that these oxides sustain redox reactions at a high positive potential which is stabilised by the presence of ferrous sulphate in the solution and, at saturation, tends to coincidence with the Flade potential. The redox process can be formulated, for example, as Fe2O3(its)+2H++2H2SO4+2e−=2FeSO4s+3H2O(1) and the potential derived from the free energy change is approximately right. γ-oxides and hydroxyoxides of iron enter into reaction more readily than their α-analogues, and this would be expected on structural grounds.
1 Emeritus Professor of Electrochemistry, Birkbeck College, University of London.
- DOI:
http://dx.doi.org/doi:10.1016/0013-4686(75)85046-8