Bimetallic iron-iridium alloy nanoparticles supported on nickel foam as highly efficient and stable catalyst for overall water splitting at large current density

Abstract In this work, FeIr bimetallic alloy self-supported on nickel foam is prepared by hydrothermal method, with average particle size of 2.17 nm and the Ir-loading is only 0.803 wt.%. It displays ultralow overpotentials for OER (200 mV) and HER (16.6 mV) at 20 mA cm−2 in alkaline media, which is superior to the ever reported HER catalysts. For overall water splitting, it only needs 1.48 V to derive a current density of 10 mA cm−2, and demonstrates an outstanding long-term stability with an ignorable decline in performance after testing 504 h at the current density of 150 mA cm−2. The excellent performance is ascribed to the ultrasmall FeIr alloy, the 3D conductive substrate, and the ethylene-glycol ligand environment facilitates highly efficient HER through hydrogen spillover. Thus, this work undoubtedly provides a promising method for developing ultralow-loading noble metal catalysts with excellent performance at large current density for overall water splitting.