Iridium-based electrocatalysts for acidic oxygen evolution reaction

Hydrogen production from water electrolysis, in particular from proton exchange membrane water electrolyzers (PEMWE), is a key approach to realizing a carbon-free energy cycle. However, the high anodic potential and strong acid in PEMWE systems pose a major challenge to the stability of electrocatalysts, and the development of efficient and corrosion-resistant catalysts is urgently needed. Currently, iridium (Ir)-based catalysts have gained great attention due to their promising activity and stability, while the extremely low reserves of Ir in the earth seriously hinder the commercialization of PEMWE. Therefore, a systematic understanding of the latest advances in Ir-based catalysts is necessary to guide their rational design to meet the industrial requirements. In this review, the general reaction mechanisms and advanced characterization techniques for mechanism recognition are first introduced. Afterwards, the systematic design strategies and performances of Ir-based catalysts, including metallic Ir, Ir oxides, and Ir-based perovskites, are summarized in detail. Finally, the conclusions, challenges, and prospects for Ir-based electrocatalysts are presented. © 2024 Science Press