Electrochemical and geometrical characterization of iridium oxide electrodes in stainless steel substrate

A geometrical and electrochemical characterization of stainless steel electrodes electrodeposited with iridium oxide (IrO2) is presented. There is a dramatic increase in the double layer capacitance (C) and an important decrease in the charge transfer resistance (R-ct) after electrodeposition, causing also a significant two orders of magnitude reduction of the electrode-electrolyte interface impedance (EEIZ). These phenomena may be explained by the fine-grained iridium oxide, which has a high grain boundary density and which increases the actual electrodic area. An RC model is presented, which would explain the electrical behaviour of the system. (c) 2008 Elsevier B.V. All rights reserved.