A Study on the Anodic Electrodeposition of Iridium Oxide on Different Substrates

Abstract

The anodic electrodeposition process of iridium oxide on Ti, Pt, Au, and glassy carbon was investigated from cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The electrocrystallization process of iridium oxide electrodeposition based on different substrates behaved consistent with the diffusion-controlled three-dimensional nucleation process, and a nucleation mode capable of expressing the process was established. Depending on the nucleation model parameters, the iridium oxide electrodeposition on Ti with the highest nucleation rate and active nucleation sites showed excellent nucleation performance, while the value of the electrodeposition on Au is the largest, indicating that Au-base electrodeposited iridium oxide can support more favorable kinetics for OER. Furthermore, the morphology and chemical composition of the electrodeposited IrOx electrodes based on different substrates were characterized by scanning electron microscope (SEM) and X-ray photoelectron microscopy (XPS), and then measured through a series of electrochemical characterization experiments. Although the SEM image of IrOx layer electrodeposited on Ti is relatively uniform and have higher IrO2 content compared to other substrates, its electrocatalytic activity is poor, while the IrOx-Au electrode exhibits the best OER performance with a current density of 10 mA cm−2 and an overpotential of 0.2 V.