Design strategies of lridium-based electrocatalysts for proton exchange membrane water electrolysis

Proton exchange membrane water electrolysis (PEMWE) has emerged as a promising technology for hydrogen production, offering high efficiency, superior hydrogen purity, and a compact system design. However, its widespread adoption is hindered by the harsh acidic environment and the intrinsically slow kinetics of the oxygen evolution reaction (OER) at the anode. Addressing these challenges requires the development of robust, acid-resistant anode catalysts. Among various candidates, iridium-based catalysts (IBCs) have attracted significant attention owing to their exceptional catalytic activity and stability under acidic conditions. Nevertheless, the high cost and limited availability of Ir impede their large-scale application. To mitigate these issues, extensive research has been devoted to strategies that reduce Ir loading while enhancing catalytic performance. This review provides a comprehensive and systematic overview of recent advances in the rational design of IBCs, focusing on strategies such as multi-scale morphology control, heteroatom doping, alloying, defect engineering, heterostructure construction, and support interactions.