Effect of coating layers on microstructure and electrochemical properties of Ti/RuO2-IrO2-TiO2 anode prepared by polymeric sol-gel method

The effect of coating layers on the microstructure and electrochemical properties of Ti/RuO₂-IrO₂-TiO₂ anode prepared by polymeric sol-gel method was systematically investigated using surface analysis techniques of SEM, EDS, XRD, and electrochemical methods of CV, EIS, potentiodynamic polarization, and accelerated life test. The results show that the area fraction of surface cracks and the coating porosity of the anode are enlarged with the increase of coating layers. The micro cracks on the above layer are affected by the surface morphology of the previous layer of the coating. As the number of coating layers is increased, the electrochemically active surface area and electrocatalytic activity of the anode are enhanced, and the accelerated lifetime of the anode is prolonged. The anode with 12 layers shows the highest utilization efficiency of the coating. The residual oxide coating after failure of the anode is increased with adding layers. The consumption rate of the coating is large for the anode with three or less layers, which is decreased obviously and then stabilized as the number of layers continues to increase.