Phosphorylated Lignin-Directed Metastable CoMoO3 Precatalyst Enables Self-Reconstructed Co-OH Active Interfaces for Durable Seawater Oxygen Evolution

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.