Highly Active Ternary Nickel-Iron oxide as Bifunctional Catalyst for Electrochemical Water Splitting

The development of noble metal free, robust catalyst is highly sought for commercialization of clean, renewable energy technology and to replace the fossil fuel-based energy equipments. Herein, we report a highly efficient and stable ternary Nickel Iron oxide (NiFe2O4) electrocatalyst for bifunctional oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline medium. The as-synthesized NiFe2O4 has been confirmed by techniques like FESEM, HR-TEM, powder X-ray diffraction (XRD), and X-ray photoelectron spectra analysis. NiFe2O4 demonstrate nanoparticle morphology with an average size of similar to 10 nm. The synthesized NiFe2O4 electrocatalyst exhibit superior electrocatalytic efficiency for OER, and achieves a current density of 10 mA cm(-2) at an overpotential of 290 mV, with smaller Tafel slope of 42 mV/dec. A stable performance of OER is obtained at 10 mA cm(-2) for more than 8 h. The electrocatalytic activity of NiFe2O4 is comparable with benchmark electrocatalyst IrO2/C. Similarly, NiFe2O4 also shows superior HER activity in 1 M KOH. The enhanced bi-functional activity of NiFe2O4 is thought to be the synergy between the multicomponent structure of NiFe2O4, high surface area, and stability leading to high electrical conductivity.