Abstract:
Polarisation data has been obtained for the CoH/CoHI and Fe'VFc111 couples at rotating disc
electrodes of platinum, gold and vitreous carbon at -30°C in ammonia acid solution. In addition,
metal wires and carbon rod have been used to examine the low level behaviour of the cobalt system
and to record charge measurements in the oxidation of the anode surfaces. The iron couple is
reversible on carbon but is inhibited by anodic films on gold and platinum. Apparent standard rate
constants for the CoH/Co111 reaction are affected only slightly by the electrode material, but the
oxidation branch is noticeably inhibited by anodic film formation. The mechanism of inhibition
by anodic films is discussed. Fe111 is unstable in acid ammonia.
