Electrodeposition of metal iron from dissolved species in alkaline media

The electrodeposition of metal iron from iron dissolved species in alkaline media has been investigated. Dissolved ferric species in equilibrium with hematite (alpha-Fe2O3) have been electrochemically identified and their reduction to iron was demonstrated. The reduction efficiency was poor, however, because of the low concentration of dissolved matter ( 2.6 x 10(-3) M ). In order to determine more precisely the electrochemical features of the deposition reaction from iron ions, more concentrated solutions at 1.9 x 10(-2) M have been obtained using an iron anode as the ion source. Voltammetric and chronoamperometric investigations using a rotating disk electrode revealed that such concentrated solutions contain ferric and ferrous species, with higher concentration of the trivalent form. Metal can be deposited with higher current efficiency in these concentrated solutions with less than 30% of the current spent in hydrogen evolution. (c) 2007 The Electrochemical Society.