Low-iridium electrocatalysts for acidic oxygen evolution

The widespread use of proton-exchange membrane water electrolysis is limited by the dynamically sluggish oxygen evolution reaction (OER), which is mediated by noble iridium-based materials as active and stable electrocatalysts. Significant efforts have been made to decrease the amount of iridium in OER catalysts without sacrificing their catalytic performances. In this frontier paper, we present the main common issues relevant to the iridium-catalyzed OER, including catalytically active species, catalytic mechanisms and activity-stability relation. We also take iridium-based perovskites as an example, and summarize the recent theoretical and experimental advances in available strategies that can lead to highly efficient, low-iridium oxygen evolution electrocatalysts under acidic conditions. Finally, we propose the remaining challenges and future directions for exploring acidic OER catalysts.