Electrochemical properties of IrO2 active anode with TNTs interlayer for oxygen evolution

A novel IrO 2 coating titanium anode (IrO 2 /TNTs/Ti) without cracks in microstructure has been prepared via a thermal decomposition method using heat-treated TiO 2 nanotube arrays (TNTs) as interlayer. This electrode shows a significantly higher activity for oxygen evolution reaction (OER) and longer lifetime than the IrO 2 /Ti electrodes without a TNTs layer. The influence of IrO 2 amount and calcination temperatures on oxygen evolution as well as morphology and phase characteristics were studied by electrochemical measurements, X-ray diffraction (XRD) and scanning electron microscopy (SEM) observations. The results show that the catalytic properties of oxide electrodes highly depended on the loading amount of IrO 2 and calcination temperatures. The electrode fabricated at calcination temperature of 600 °C showed a weak electrocatalytic activity due to high degree of crystallinity, grain growth, accumulation of active component and the collapse of TNTs. On the contrary, the IrO 2 /TNTs/Ti electrode prepared at low calcination temperature (400 °C) possesses extremely more surface active sites and high activity for oxygen evolution in the initial stage, but its service life is very short. The IrO 2 /TNTs/Ti electrode was found to achieve the lowest film resistance and the charge transfer resistance at an optimal loading amount of 6 g/m 2 . By simply optimizing both calcination temperature and IrO 2 loading amount, IrO 2 /TNTs/Ti electrode with high activity and long lifetime can be fabricated.