NixFeyN@C microsheet arrays on Ni foam as an efficient and durable electrocatalyst for electrolytic splitting of alkaline seawater

Abstract

Self-supported nickel–iron nitride microsheet arrays coated with carbon are grown on commercial Ni foam (Ni_xFe_yN@C/NF) and used as an electrocatalyst for splitting of alkaline seawater. The porous architecture and superhydrophilic/superaerophobic surface ensure sufficient exposure of active sites and mass transfer. The synergetic coupling effect between the carbon coating and Ni_xFe_yN facilitates electron transport. The optimal anode (Ni₃FeN@C/NF) and cathode (Ni₃N@C/NF) electrocatalysts are employed to assemble a two-electrode seawater electrolyzer for overall alkaline seawater electrolysis, which delivers a large current density of 500 mA cm⁻² at a low cell voltage of 1.91 V. The superior corrosion-resistance and electron conductivity of the electrocatalyst are responsible for its excellent durability up to 100 hours. This result suggests that transition-metal nitrides coated with carbon offer an effective route to fabricate high-performance and durable hybrid electrocatalysts for hydrogen production from seawater electrolysis.