Dissolution of Co ₃ O ₄ in Acidic Oxygen Evolution Reaction: Fundamentals and Mitigation Strategies

The widespread adoption of proton exchange membrane water electrolyzers (PEMWEs) is hindered by the scarcity and cost of Ir‐based catalysts required for the kinetically sluggish oxygen evolution reaction (OER) in acidic media. Spinel cobalt oxide (Co 3 O 4 ) has emerged as a promising non‐precious candidate due to its favorable intrinsic activity and tunable electronic structure. However, its practical application is fundamentally limited by severe dissolution and degradation under the harsh acidic and anodic conditions of PEMWE operation. This review provides a comprehensive examination of the dissolution mechanisms of Co 3 O 4 during acidic OER, focusing on the critical roles of the lattice oxygen evolution reaction (LOER) and potential‐driven surface reconstruction. We further synthesize recent advances in stabilization strategies, including the application of protective coatings, rational elemental doping, and innovative electrolyte engineering. Finally, we present a critical outlook on future research directions, emphasizing the need for advanced in situ characterization, machine‐learning‐aided design, and the development of realistic testing protocols to bridge the gap between fundamental research and practical application.