Stable Seawater Electrolysis Over 10 000 H via Chemical Fixation of Sulfate on NiFeBa-LDH

Abstract

Although hydrogen production through seawater electrolysis combined with offshore renewable energy can significantly reduce the cost, the corrosive anions in seawater strictly limit the commercialization of direct seawater electrolysis technology. Here, it is discovered that electrolytic anode can be uniformly protected in a seawater environment by constructing NiFeBa-LDH catalyst assisted with additional SO₄²⁻ in the electrolyte. In experiments, the NiFeBa-LDH achieves unprecedented stability over 10 000 h at 400 mA cm⁻² in both alkaline saline electrolyte and alkaline seawater. Characterizations and simulations reveal that the atomically dispersed Ba²⁺ enables the chemical fixation of free SO₄²⁻ on the surface, which generates a dense SO₄²⁻ layer to repel Cl⁻ along with the preferentially adsorbed SO₄²⁻ in the presence of an applied electric field. In terms of the simplicity and effectiveness of catalyst design, it is confident that it can be a beacon for the commercialization of seawater electrolysis technology.