Cobalt‐Based Catalysts for Electrochemical Water Splitting: A Review of Mechanisms, Performance, and Applications

ABSTRACT The development of efficient, stable, and earth‐abundant electrocatalysts is critical for advancing electrochemical water splitting as a sustainable hydrogen production technology. Among non‐precious candidates, cobalt‐based materials have garnered significant attention due to their structural versatility and tunable electronic properties. This review comprehensively examines recent progress in cobalt‐based catalysts for the hydrogen and oxygen evolution reactions. We discuss key optimization strategies, including nanostructuring, heteroatom doping, and defect/interface engineering, that enhance activity and stability by increasing active site density, improving conductivity, and optimizing intermediate adsorption energetics. A particular focus is placed on the dynamic reconstruction of pre‐catalysts into active (oxy)hydroxide phases under operational conditions, a crucial consideration for rational design. By integrating mechanistic insights from advanced in situ characterization and theoretical calculations, we elucidate structure‐activity relationships and reaction pathways. Finally, we outline persistent challenges and future directions, emphasizing the need for standardized evaluation and the design of durable catalysts capable of operating at industrial‐scale current densities to bridge the gap between laboratory research and practical application.