Promoting the Corrosion Resistance of Mo-FeCoP@MnO_x/NF via Double Protection Mechanisms Toward Electrolysis of Seawater at Ampere-Level Current Density

Producing hydrogen via seawater electrolysis is pivotal for addressing both energy and environmental crises. An industrial-current-density electrocatalyst consisting of Mo-doped FeCoP nanorods decorated with MnO_x nanosheets is elaborately designed and grows in situ on nickel foam forming hierarchical Mo-FeCoP@MnO_x/NF (M-FCP@MnO_x/NF) for seawater electrolysis. Density functional theory calculations demonstrate that MnO_x species remarkably reduce the adsorption capacity of Cl⁻, which enhances the corrosion resistance and selectivity of M-FCP@MnO_x/NF during seawater electrolysis. Moreover, incorporating high-valence Mo species forms a superficial electrostatic layer on electrocatalysts to repel Cl⁻. Owing to its enhanced double protection mechanism and unique self-healing characteristics, M-FCP@MnO_x/NF requires overpotentials of only 209 mV (HER) and 270 mV (OER) to reach a current density of ≈1.0 A cm⁻² and maintains stable operation over 120 h during alkaline electrolysis of seawater. The colorimetric analysis indicates negligible ClO⁻ production post stability test, indicating that the OER selectivity approaches 100%.