Establishing Performance Baselines for the Oxygen Evolution Reaction in Alkaline Electrolytes

Abstract

This paper establishes baseline performance of several platinum group metal (PGM) and non-PGM catalysts in alkaline oxygen evolution (OER). As OER catalyst development efforts increase, there is a need to standardize testing and baseline performance to compare catalysts between different studies, better direct materials development, and understand how performance improvements translate to the device. Of the catalysts tested, metals tend to have higher half-cell activity than their fully oxidized counterparts. In single-cells, however, metal activities approach oxides, likely due to the elevated temperature, higher potential, and longer time needed to condition membrane electrode assemblies (MEAs) relative to rotating disk electrodes (RDEs). In RDEs, cobalt (Co) and ruthenium nanoparticles are the most OER active. Due to high ruthenium dissolution rates, however, iridium (Ir) is used as a PGM baseline. Activity differences between materials in RDE (Ir 320 A g‒1, Co 12 A g‒1 at 1.55 V) further appear to translate to MEAs (Ir 1370 A g‒1, Co 101 A g‒1 at 1.5 V), indicating that half-cell testing can be useful in the early stages of catalyst development to predict kinetics at the device-level.