Catalysts for Acidic Oxygen Evolution Reaction

The acidic oxygen evolution reaction (OER) is a key half-reaction underpinning proton exchange membrane water electrolysis (PEMWE), a promising technology for the industrial production of high-purity green hydrogen. However, under harsh acidic conditions of OER, even highly active metals are prone to corrosion and dissolution, leading to rapid performance degradation, particularly at industrially relevant current densities. Therefore, developing acidic OER catalysts that simultaneously exhibit high intrinsic activity with long-term stability remains a core scientific and engineering challenge for the practical deployment of PEMWE. This review first outlines the fundamental mechanisms of acidic OER, including the adsorbate evolution mechanism (AEM), the lattice oxygen mechanism (LOM), and the oxide path mechanism (OPM). It then summarizes recent advances in catalyst design and structure-property relationships, with emphasis on strategies for stabilizing Ru-based catalysts, reducing Ir loading while enhancing site efficiency in Ir-based systems, and developing platinum group metals (PGM)-free catalysts featuring acid-stable frameworks, corrosion-resistant architectures, and improved electronic conductivity. Finally, it discusses the remaining challenges and future directions in acidic OER catalysis, providing insights to guide the rational design of high-performance anode catalysts for next-generation PEMWE systems.