A mixture design approach to thermally prepared Ir-Pt-Au ternary electrodes for oxygen reduction in alkaline solution

Thermally prepared ternary Ir-Pt-Au electrodes were investigated experimentally over their entire compositional range using the mixture design method. The results, involving voltammetric charges from electrode redox (q*), oxygen reduction current densities (i), and their correspondingly electrocatalytic activities (i/q*), are examined through regression models and response surface contour plots. Using mixture experimental design, the empirical models are fitted and plotted as contour diagrams which facilitate comparisons with experimental trends noted by other investigators and reveal the synergistic/antagonistic effects between the mixed oxides. The material characterization was performed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) to assist in interpreting the electrocatalytic activity for oxygen reduction.