ZIF-8 derived NiFe hydroxide on nickel foam for robust water oxidation.

• NiFe hydroxide is prepared via ion-assisted method with ZIF-8 as precursor. • Ni 0.75 Fe 0.25 (OH) 2 /NF shows low overpotential of 259 mV at 100 mA cm−2. • The NiFe bimetal effect and nanosheets with oxygen vacancies are key for OER. Developing active water oxidation electrocatalysts with earth-abundant components is significant for bulk hydrogen supply via water electrolysis. Herein, nickel iron hydroxide nanosheets assembled particles on nickel foam are prepared through ion-assisted etching method with ZIF-8 as precursor. The sample achieves remarkable catalysis efficiency toward oxygen evolution reaction with ultralow overpotential of 259 mV at high current density of 100 mA cm−2. The superior catalysis efficiency is assigned to Ni/Fe synergisms of optimized intrinsic activity, abundant surface oxygen vacancies, enhanced charge flow, and increased active sites, as well as nanosheet structure benefits of approachable catalytic sites and shortened charge transform pathways. [ABSTRACT FROM AUTHOR]