Influence of a Nanoscale Gold Thin Layer on Ti/SnO₂-Sb₂O₅ Electrodes

A nanoscale gold thin film and its influence on Ti/SnO 2 -Sb 2 O 5 coating have been investigated by scanning electron microscopy (SEM) and electrochemical methods such as cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and the chronopotentiometric technique in both acidic and caustic solutions. The gold thin film was fabricated by sputtering, and its thickness was estimated using electrochemical methods. The nanoscale gold thin film on the titanium substrate exhibits electrochemical behavior similar to that of a polycrystalline Au electrode. Our study shows that the presence of a nanoscale Au thin film on the Ti substrate can effectively prevent the growth of a TiO 2 insulating layer between the substrate and the SnO 2 -Sb 2 O 5 coating, resulting either from the thermal procedure during the fabrication of the oxide electrodes or from the electrochemical process during the lifetime tests, thus greatly prolonging the service lifetime of the SnO 2 -Sb 2 O 5 electrodes. The failure mechanisms of the SnO 2 -Sb 2 O 5 electrodes have also been studied using the EIS and SEM techniques.