REACTION OF OXYGEN REDUCTION ON THE SURFACE OF AU ON TI WITH OXIDE FORMED POTENTIODYNAMICALLY BEFORE AND AFTER THE DEPOSITION OF AU

Abstract

One of the most important reactions for electrochemical science and technology is the electrocatalytic reduction of oxygen. It is particularly relevant in fuel cells because it is slow to react and requires high overpotentials. This work aims to study electrodes with deposits of Au on Ti obtained by electrodeposition. The substrates have undergone potentiodynamic growths of oxides before deposition for some electrodes and after deposition for other electrodes under study, at different final potentials. Both procedures resulted in the formation of a composite Au layer on the Ti surface. The electrochemical behavior of these composite layers was examined in a 0.01 M HClO₄ solution, both oxygen-free and oxygen-saturated, and compared with the behavior of Ti as a target, using the cyclic voltammetry technique. In the potential region of the oxygen reduction reaction (RRO), the Au layer on the Ti obtained by first performing the Au deposition and then the growth of the anode oxide showed a better response, not only in the onset potential of the RRO, but also in the current densities. In all cases the voltammetry curves of the Au and TiO₂ composite layers were similar to those shown by the Au polycrystalline.