A study on the performance of IrO2–Ta2O5 coated anodes with surface treated Ti substrates

Oxalic acid etching and hydrogen treatment were applied on Ti substrates of IrO2–Ta2O5 coated anodes. The coatings were prepared by thermal decomposition of a mixture of H2IrCl6·6H2O dissolved in hydrochloric acid and TaCl5 dissolved in alcohol. Surface morphology, microstructure, matter phase, electrochemical properties and accelerated life of the anodes were observed and examined. Compared with the anode without its substrate treated, the anodes with the substrates oxalic acid etched and hydrogen treated at 300 °C, 400 °C, 500 °C and 600 °C respectively show better electro-catalytic performance and longer life. However, effects of two methods are different. Oxalic acid etching of the substrate, which could get better improvement at accelerated life, while hydrogen treatment of the substrates, which could get better improvement at the electro-catalytic performance. Especially, anode with 400 °C hydrogen treated substrate has the highest electro-catalytic activity.