Dynamic Hydroxyl Replenishment to Stabilize Lattice Oxygen Via Polyhydroxy Metal Ions Mediation in Seawater Electrolysis

ABSTRACT Seawater oxidation reaction (SOR) offers a sustainable route for hydrogen production, but imposes stringent requirements on catalysts. Under operating conditions, catalysts must maintain high oxygen evolution reaction (OER) activity, excellent selectivity, and resistance to chloride ion corrosion. Herein, to address the bottlenecks in catalytic activity and durability of nickel‐based catalysts for SOR, a dynamic hydroxyl healing lattice oxygen mechanism (DH‐LOM) has been developed. By creating a polyhydroxy metal ion microenvironment in an alkaline seawater system, the local electronic environment of the catalysts can be regulated to enhance OER activity. This mechanism promotes oxygen vacancy mediated hydroxyl exchange, enabling rapid dynamic repair of active NiOOH species at the solid–liquid interface, while also facilitating interfacial hydroxyl capture to increase local reactant concentration and specifically shield chloride ions to inhibit side reactions. Furthermore, it can extend the lifetime of Ni‐HHTP from the initial tens of hours to over 500 h. This strategy exhibits universality and can be extended to NiOOH‐reconstructed catalysts and other polyhydroxy systems. Under the operating conditions (60°C, 1 A cm −2 ), THZ‐Ni‐HHTP||Pt/C achieved stable seawater electrolysis for 1100 h. The dynamic hydroxyl self‐healing lattice oxygen‐mediated mechanism provides a new view for the development of durable seawater oxidation catalyst microenvironment.