Highly Active and Stable Iridium Pyrochlores for Oxygen Evolution Reaction

Abstract

Proton exchange membrane water electrolysis (PEMWE) is a promising technology for electricity-to-fuel conversion which allows for direct production of hydrogen from water. One of the key problems limiting widespread implementation of PEMWE into energy systems is the sluggish kinetics of the anodic process: the oxygen evolution reaction (OER). Additionally, state-of-the-art OER materials contain large amounts of low abundant noble metals (Ru, Ir), and therefore, development of low-cost, highly active and stable OER catalysts remains an important challenge. We developed a synthetic approach to the iridium pyrochlores–complex oxides of iridium with reduced content of the noble metal as compared to IrO2. The materials were synthesized from molten sodium nitrate (Adams fusion method) at moderate temperatures (500–575 °C) and consist of highly crystalline iridium pyrochlore nanoparticles with surface areas of up to 40 m2 g–1, which is a significant improvement compared to the traditional high temperature solid-...