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.