Engineered Nickel–Iron Nitride Electrocatalyst for Industrial-Scale Seawater Hydrogen Production

Seawater electrolysis under alkaline conditions is a crucial technology for sustainable hydrogen production. However, achieving the long-term stability of the electrocatalyst remains a significant challenge. In this study, it is demonstrated that surface reconstruction of a transition metal nitride (TMN) can be used to develop a highly stable oxygen evolution reaction (OER) electrocatalyst. Rapid introduction of phosphate groups (PO₄³⁻) accelerates the in situ surface reconstruction of Ni₃FeN, generating a catalyst, with a conductive nitride core and Cl⁻-resistant hydroxide shell that demonstrates outstanding performance, maintaining stability for over 2500 h at 1 A cm⁻² current density in alkaline seawater. In situ characterization and density functional theory (DFT) calculations reveal the dynamic evolution of active sites, providing insights into the mechanisms driving long-term stability. This work not only introduces an efficient approach to TMN-based catalyst design but also advances the development of durable electrocatalysts for industrial-scale seawater hydrogen production.