Rotating Ring-Disk Electrode Voltammetry Considering the Quasi-Four Electron Reduction of Oxygen for Fe/N/C Catalysts

摘要

Understanding the mechanism of the oxygen reduction is quite important to develop active cathode catalysts. This study demonstrates a novel analysis method to handle the oxygen reduction reaction (ORR) that includes both the four-electron and two-electron pathways. In this study, hydrogen peroxide voltammetry was conducted separately to evaluate the rate constant of the hydrogen peroxide reduction reaction (HPRR) more accurately, and the obtained data were combinatorially analyzed with those from the ORR experiments. First, mathematical modification of the conventional Damjanovic approach was carried out, and then a novel reaction model that considers the quasi-four-electron pathway was utilized to avoid overestimation of the four-electron pathway. ORR and HPRR voltammetry was carried out for a Fe/N/C catalyst and the same data were analyzed with the conventional Damjanovic-Hsueh method and newly proposed two methods, and the overestimation of four-electron pathway was successfully removed.