Electrochemical properties of IrO2-Ti2O5-Co3O4 coated Ti anode in acid media
By Alanazi, Nayef M.; Al-Abdulhadi, Abdullatif I.; Al-Zharani, Talal Y.; Al-Khaldi, Turki A.; Alghamdi, Rasha A.; Ali, Anaam H. Al-Shaikh; Shen, Shouwen
Published in Surface and Coatings Technology
2019
Abstract
Iridium oxide-tantalum pentoxide (IrO2–Ta2O5) coated anodes were prepared by thermal decomposition on a tubular titanium substrate with and without cobalt salts containing a precursor. The surface morphology and microstructure of the deposited coatings were investigated by use of an environmental scanning electron microscope (ESEM), X-ray fluorescence (XRF) spectrometry and scanning transmission electron microscope (STEM). The electrochemical properties of the deposited thin coatings were examined by cyclic voltammetry, potentiodynamic polarization scan and electrochemical impedance spectroscopy (EIS) techniques. The service life cycle of the applied coatings was evaluated under electrolysis at a constant current density of 1 A cm−2 in 1 M sulfuric acid (H2SO4) solution. The role of cobalt oxide (Co3O4) in the electrocatalytic activity and stability of IrO2–Ta2O5 coating are discussed. A small amount of Co3O4 resulted in improving the life cycle of the IrO2-Ta2O5 anode in the 1 M H2SO4 solution due to dense nature coating. Meanwhile, the Co3O4 had no significant contribution to the electrochemical measurements.