Electronic structure modulation of NiIr(OH)6 perovskite hydroxide for chlorine-resistant electrolytic seawater
Direct seawater electrolysis offers a cost-effective route to clean hydrogen, but the competitive chlorine evolution reaction (CER) and electrode corrosion impede practical deployment. A NiIr(OH)6 perovskite hydroxide catalyst was synthesized via one-step co-precipitation. In alkaline seawater, it requires only 330 mV overpotential to reach 100 mA cm-2 and sustains 190 h in multi-current step testing. In situ Raman spectroscopy shows that Ir species promote the formation of active NiOOH phases, accelerating oxygen evolution reaction (OER) kinetics. Density functional theory calculations reveal that Ir doping modulates the electronic structure of Ni and Ir sites, strengthening OH adsorption (-2.09 eV) and suppressing Cl- adsorption (-1.38 eV), thereby enhancing OER selectivity. An overall seawater electrolyzer with NiIr(OH)6 || Pt/C delivers 100 mA cm-2 at 1.63 V and operates stably for over 100 h. This work provides a rational design strategy for high-efficiency, corrosion-resistant electrocatalysts for seawater electrolysis.