Zn-doped nickel iron (oxy)hydroxide nanocubes passivated by polyanions with high catalytic activity and corrosion resistance for seawater oxidation

Electrochemical water splitting to produce hydrogen fuel is a promising renewable energy-conversion technique. Large-scale electrolysis of freshwater may deplete water resources and cause water scarcity worldwide. Thus, seawater electrolysis is a potential solution to the future energy and water crisis. In seawater electrolysis, it is critical to develop cost-effective electrocatalysts to split seawater without chloride corrosion. Herein, we present zinc-doped nickel iron (oxy)hydroxide nanocubes passivated by negatively charged polyanions (NFZ-PBA-S) that exhibits outstanding catalytic activity, stability, and selectivity for seawater oxidation. Zn dopants and polyanion-rich passivated surface layers in NFZ-PBA-S could effectively repel chlorine ions and enhance corrosion resistance, enabling its excellent catalytic activity and stability for seawater oxidation.