Ternary metal-based inverse spinel oxide NiCrFeO₄ nanoparticles as a highly efficient oxygen evolution catalyst

The development of a cost-effective and highly efficient oxygen evolution reaction (OER) catalyst gain significant importance in sustainable energy conversion and storage applications. Herein, we develop a series of ternary metal-based inverse spinel oxide (ISO) compound, NiCr_xFe_2-xO₄ (x: 0, 0.2, 0.4, 0.6, and 1.0) support with carbon for an efficient OER catalyst. Systematic studies are performed to understand the extrinsic and intrinsic properties of the developed ISO compounds via tuning the physical properties and varying the compound composition. The optimized ternary ISO compound (x = 1; NiCrFeO₄) delivers the superior OER kinetics with a remarkable low overpotential value of 264 mV at a 10 mA cm⁻² current density and a low Tafel value of 45 mV dec⁻¹ under 1 M KOH. In addition, the full cell water electrolysis at a current density of 10 mA cm⁻² shows an exceptional long-term stability of 40 h in comparison with commercial catalyst support electrolysis cell. This work emphasizes the rational strategies to unveil the efficient OER catalyst for alkaline water electrolysis.