Self-Supported Nanostructured Iridium-Based Networks as Highly Active Electrocatalysts for Oxygen Evolution in Acid

Due to the slow kinetics of the oxygen evolution reaction (OER), high precious metal loadings are currently required at the anode of proton exchange membrane (PEM) electrolyzers. In this work, we present a novel, scalable and efficient method for the fabrication of high surface area iridium-based electrocatalysts. Using alternating sputtering of iridium and cobalt, followed by selective leaching, we produce a self-supported and highly active OER electrocatalysts for acidic environment. Nanostructured IrOx-networks present a bulk-like behaviour, with a site-specific activity similar to extended polycrystalline IrOx surfaces. Moreover, in terms of mass activity, the IrOx-networks are among the most active Ir-based catalysts reported, presenting a mass activity enhancement by a factor of eight over commercial Ir-black nanoparticles. These novel self-supported Ir-based networks are very stable, which, combined with their enhanced mass activity, make them promising as anode catalysts for PEM electrolyzers.