Electro-catalytic study of IrO2Ta2O5 coated anodes with pretreated titanium substrates

Pre-treatment such as oxalic acid etching, nitrogen treatment and hydrogen treatment were applied on the titanium substrates of IrO2Ta2O5 coated anodes. The IrO2Ta2O5 coatings were prepared by traditional thermal decomposition with mixing H2IrCl6·6H2O dissolved in hydrochloric acid and TaCl5 dissolved in alcohol with a mole ratio of 7:6. SEM, FESEM and XRD were employed to observe the surface morphology and analyze the matter phases of the anodes. CV and EIS were employed to study the electrochemical properties of the anodes. Mott-Schottky was employed to analyze the semiconducting behavior of the anodes. The anode with hydrogen treated substrate at 600 °C had the largest real surface area and the best electro-catalytic activities of all the anodes. The anode with nitrogen treated substrate at 600 °C did not own the best electro-catalytic activities, but its semiconducting behavior exhibited the advantage of being conducive to oxygen evolution.