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

A novel IrO2 coating titanium anode (IrO2/TNTs/Ti) without cracks in microstructure has been prepared via a thermal decomposition method using heat-treated TiO2 nanotube arrays (TNTs) as interlayer. This electrode shows a significantly higher activity for oxygen evolution reaction (OER) and longer lifetime than the IrO2/Ti electrodes without a TNTs layer. The influence of IrO2 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 IrO2 and calcination temperatures. The electrode fabricated at calcination temperature of 600 degrees 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 IrO2/TNTs/Ti electrode prepared at low calcination temperature (400 degrees 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 IrO2/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 IrO2 loading amount, IrO2/TNTs/Ti electrode with high activity and long lifetime can be fabricated. (C) 2017 Elsevier B.V. All rights reserved.