Ni-X (X = Cl, Br) Reaction Energy Barrier Regulation in Passive Film for Stable Oxygen Evolution Reaction in Alkaline Seawater.

Abstract

Seawater electrolysis offers a promising route for green hydrogen production, but anode corrosion by chloride (Cl^-) and bromide (Br^-) ions hinders its practicality. Although effective catalyst modification strategies have been developed to mitigate Cl^--induced corrosion, the extensive spallation of the catalyst layer caused by accumulated Br^- highlights the urgent need to address co-corrosion by both Br^- and Cl^-. Here, a Ni-X (X = Cl, Br) reaction energy barrier modulation strategy is proposed by alloying the Ni substrate to enhance the corrosion resistance of the surface passive film. Theoretical simulations predict that NiCr alloy has substantial potential as an anode substrate. Experimental results further demonstrate that the unique passive film of NiCr can resist both Cl^- and Br^-, with a much higher pitting potential compared to alternative materials, effectively preventing harmful Br^--induced lateral corrosion. As validation, a typical NiFe-LDH catalyst grown on a NiCr mesh exhibits over 15 times the stability of the same catalyst on a Ni mesh, achieving >2000 h of stability in concentrated seawater and >1000 h of stable operation at 60 °C in an industrial electrolyzer device.