INSITU FTIR SPECTROSCOPY OF IRON ELECTRODES IN ALKALINE-SOLUTIONS .2. EXTERNAL REFLECTION ABSORPTION-SPECTROSCOPY

The electrochemical reactions proceeding on iron electrodes in 5 and 1M KOH were investigated by in situ FTIR spectroscopy using external reflection absorption geometry. Two different spectroscopic techniques were applied: the linear potential sweep—Fourier transform infrared spectroscopy (LPS-FTIRS) technique, which is described in this paper, and a modified version of the subtractively normalized interfacial Fourier transform infrared spectroscopy (SNIFTIRS) method. We found Fe(OH)2 to be the product of the oxidation reaction Fe(0) → Fe(II) and of the reduction process Fe(III) → Fe(II); δ-FeOOH or α-FeOOH are the oxidation products of the reaction Fe(II) → Fe(III). Furthermore, we found magnetite to be a product formed partly irreversibly at higher cycle numbers. © 1990, The Electrochemical Society, Inc. All rights reserved.