A simple self-corrosion method constructs the Ni 3 S 2 @FeOOH heterostructure enables industrialized seawater oxidation

Abstract

Electrocatalytic seawater splitting holds immense promise as a green hydrogen production technology; however, the anodic oxygen evolution reaction (OER) confronts formidable challenges arising from the high concentration of chloride ions (Cl -) and other impurities in seawater. Herein, we develop a facile two-step immersion corrosion strategy to successfully construct a Ni 3 S 2 @FeOOH heterojunction electrocatalyst on nickel foam (NF) tailored for industrial alkaline seawater oxidation. Integrating density functional theory (DFT) calculations and experimental characterizations, we demonstrate that Ni 3 S 2 @FeOOH selectively enriches OH -while repelling Cl -during OER in alkaline seawater electrolytes. Notably, in situ leaching of SO 4 2-from the electrode triggers efficient self-reconstruction, facilitating the generation of high-valence metal active sites. The asfabricated catalyst exhibits remarkable OER performance with a low overpotential of 390.5 mV at an ultrahigh current density of 1000 mA cm -2 in alkaline seawater. Moreover, it maintains exceptional electrochemical stability for over 1000 hours at the industrial current density of 1000 mA cm -2 . This work provides a scalable strategy for constructing self-reconstructing electrocatalysts that promote highvalence metal site formation and efficient Cl -repulsion in alkaline seawater oxidation.