On the mechanism of iron reduction from alkaline solutions

Abstract

Comparison of the data on the reduction of hydrated iron oxide present in the form of a suspension in concentrated KOH solutions and of the hydroxide deposited on the cathode in the form of a compact film shows that in the latter case, along with the process of ferrite ion reduction from the solution, there occurs also a reduction in the solid phase; in both cases the reduction results in the formation of metallic iron. The partial polarization curve of iron reduction (plotted from the data on the dependence of the current strength upon the rotation rate of the disk electrode) shows the regions of limiting diffusion currents for the ferrite ion corresponding to its reduction to hypoferrite ion and to the reduction of the latter to metallic iron. A sharp decrease in the current over a narrow potential range (−1·25 to −1·30 V) is considered in conjunction with the data on the role of the point of zero charge in the processes of reduction of anions and on the possibility of a co-deposition of alkali metal, as the reason for the shift in the potential of zero charge.