Transition Metal-Coordinated Polymer Achieves StableSeawater Oxidation over NiFe Layered Double Hydroxide

Seawater electrolysis has emerged as a promising approach for the generation of hydrogen energy, but the production of deleterious chlorine derivatives (e.g., chloride and hypochlorite) presents a significant challenge due to the severe corrosion at the anode. Transition metal-coordinated polymers have garnered attention as promising electrocatalysts for alkaline seawater oxidation (ASO), attributed to their remarkable chlorine corrosion resistance, high conductivity, and facile synthesis. In this study, we employ an anodic oxidation-electrodeposition strategy to grow NiFe-polyaniline on NiFe layered double hydroxide supported on Ni foam (NiFe LDH@NiFe-PANI/NF) as a highly efficient catalyst for ASO. We demonstrate stable ASO at industrial-level current densities (<i>j</i>) by employing a synergistic strategy that integrates NiFe-PANI, which offers resistance to chlorine-induced corrosion, and molybdate, which effectively repels chloride anions. In alkaline seawater, NiFe LDH@NiFe-PANI/NF requires 380 mV to sustain a <i>j</i> of 1000 mA cm^–2, and it exhibits continuous operation for 500 h at a <i>j</i> of 1000 mA cm^–2. Besides, the anion-exchange membrane electrolyzer consisting of NiFe LDH@NiFe-PANI/NF requires a voltage of 2.16 V to drive 300 mA cm^–2. Notably, it can operate stably for 120 h, highlighting its potential for sustainable energy applications.