A study on Ti anodic pretreatment for improving the stability of electrodeposited IrO₂ electrode

The anodization pretreatment, in hydrofluoric acid with different concentrations, was applied on titanium for improving the stability of electrodeposited IrO₂/Ti electrodes. A developed plating bath was adopted to electrodeposit IrO₂ on titanium substrates pretreated by three different pretreatment methods. The morphological characteristics, microstructure, electro-catalytic activities, and stability of electrodeposit IrO₂ electrodes were observed and examined. In all cases, the hydrofluoric acid anodization improved the homogeneity and evenness of titanium substrates as well as the deposits. Among all samples, the electrodes with 1.0 wt% HF anodization exhibited the highest electro-catalytic activities and the ones with 0.5 wt% HF anodization exhibited the longest accelerate life time. The results indicate that anodization pretreatment in hydrofluoric acid has certain impacts on electrodeposited IrO₂/Ti electrodes, although the effects depend on HF concentration. It might be suggested that a porous-structure was generated on titanium surface with hydrofluoric acid anodization, which may influence IrO₂ electrodeposition, and thus the electro-catalytic activities and stability of such electrodes.