Ir nanoparticles decorated NiFe metal–organic framework as a highly efficient and stable heterostructure electrocatalyst for overall seawater splitting†

Developing a bifunctional electrocatalyst for overall seawater splitting is crucial for advancing sustainable hydrogen (H₂) production. However, at industrial current densities, anodic chlorine chemical corrosion and cathodic sluggish hydrogen evolution kinetics will seriously hinder the system of seawater-to-H₂. Herein, we present a heterojunction electrocatalyst synthesized via hydrothermal methods to create ultrathin NiFe-MOF nanosheets on nickel foam, followed by the deposition of Ir nanoparticles through a redox strategy (Ir@NiFe-MOF/NF). Ir@NiFe-MOF/NF demonstrates exceptional alkaline seawater oxidation and reduction properties, achieving a current density of 1000 mA cm⁻² with overpotentials of 445 and 233 mV. Additionally, it requires only a voltage of 2.11 V to drive 250 mA cm⁻² in a membrane electrode device and operates stably for 400 hours in alkaline seawater, surpassing other recently reported bifunctional electrocatalysts.