Phosphorylated Lignin‐Directed Metastable CoMoO 3 Precatalyst Enables Self‐Reconstructed Co‐OH Active Interfaces for Durable Seawater Oxygen Evolution

ABSTRACT Efficient seawater oxygen evolution requires electrocatalysts that combine high activity, chloride tolerance, and long‐term durability. Herein, a phosphorus–lignin ligand strategy is developed to construct an activation‐prone P‐CoMoO 3 @PLC precatalyst. Phosphorylated lignin enables homogeneous Co/Mo coordination, lattice P incorporation, oxygen‐vacancy generation, and conductive carbon confinement, producing a metastable CoMoO 3 lattice with perturbed Co‐P‐Mo/Co‐O‐Mo coordination environments. P‐CoMoO 3 @PLC requires only 180 mV at 10 mA cm −2 in simulated seawater, and sustains 500 mA cm −2 in natural seawater, outperforming commercial RuO 2 in durability. Operando analyses reveal an activation‐induced dissolution–reconstruction pathway, in which partial Mo/P leaching converts the precatalyst into a Co(OH) 2 ‐derived CoOOH‐rich interface coupled with residual CoMoO 4 . Co(OH) 2 ‐like species serve as hydroxylated intermediates, whereas CoOOH‐like sites constitute the active OER phase; residual CoMoO 4 and the lignin‐derived carbon matrix stabilize the reconstructed layer and promote charge transport. DFT calculations further show favorable *OH formation but thermodynamically unfavorable *Cl adsorption, explaining the preferential OER pathway and suppressed chlorine‐related reactions. This work establishes bio‐ligand metastability and reconstruction‐driven interface engineering as a robust design strategy for seawater electrolysis.