Key Descriptors for Stability Regulation of Ru‐Based Catalysts in Acidic Oxygen Evolution

ABSTRACT Driven by the global energy transition, proton exchange membrane water electrolysis (PEMWE) has become a pivotal technology for green hydrogen production. However, its large‐scale application is hindered by the high cost of iridium (Ir)‐based catalysts and the insufficient stability of ruthenium (Ru)‐based catalysts under acidic oxygen evolution reaction (OER) conditions. To facilitate the rational design of durable Ru‐based catalysts, this review systematically summarizes the current understanding of the stability of Ru‐based acidic OER catalysts from the perspective of degradation mechanisms and stability descriptors. We begin by dissecting the fundamental origins of catalyst deactivation, with emphasis on two primary degradation pathways, namely Ru dissolution and lattice oxygen instability‐induced amorphization and phase transformation. Building upon these degradation mechanisms, we construct a comprehensive stability‐oriented descriptor framework that encompasses active‐site stability descriptors and lattice oxygen stability descriptors. The intrinsic correlations between these descriptors and catalyst degradation behaviors are systematically discussed, followed by representative descriptor‐guided catalyst design strategies. Finally, we outline the remaining challenges and future opportunities in descriptor‐driven catalyst development. Overall, this review integrates degradation mechanisms with quantitative stability descriptors to establish a unified understanding of Ru catalyst stability, providing practical guidance for the rational design of durable acidic OER electrocatalysts for PEMWE applications.