Optimized performance of nickel in crystal-layered arrangement of NiFe2O4/rGO hybrid for high-performance oxygen evolution reaction

To rescue the future from the global energy crisis and to ensure it with clean and economical hydrogen energy, it is an urgency to develop an efficient OER catalyst, which intensely sluggish the kinetic process of hydrogen production. Herein, we have precisely synthesized an efficient, stable, earth-abundant metal-based NiFe2O4/rGO hybrid OER electrocatalysts by a simple solvothermal method. The measurements including XRD, FTIR, XPS, EDS, SEM, and TEM revealed the prominent structural integrity of catalyst with crystal-layered structure. The rich oxidation chemistry of transition metals and substantially active carbon substrate allows tuning of their electronic properties concerning their concentration, composition, and morphology. The effect of different Ni wt.% (0%, 2%, 4%, and 6%) on the morphology of hybrid as well as on electrochemical performance investigated. The protocols like overpotential required to achieve a current density of 10 mA/cm2, Tafel slope, ECSA, RF, EIS, stability was utilized to examine the overall abilities of electrocatalyst in alkaline 1 M KOH solution. The optimized NiFe2O4/rGO hybrid with 2 wt % Ni exhibited the excellent OER performance, which delivers a current density of 10 mA/cm2 at an overpotential of only 302 mV with a small Tafel slope of 63 mV/dec. The high activity of the catalyst is attributed to the synergistic effect of the crystal-layered structure as well as rapid mass-charge transfer. Such, rational design concept of anchoring non-precious metal on carbon in a controlled manner, offering splendid flexibility to tailor electrochemical OER performance. The optimized variations in metal concentration and morphologies, providing a promising route to develop a cost-effective catalyst for advanced energy conversion applications. [Display omitted] •NiFe2O4/rGO hybrid shows superior activity for OER.•Only 302 mV overpotential to deliver 10 mA/cm2 with a 63 mV/dec Tafel slope.•High performance attributed to the synergistic effect of crystal-layered structure.•The optimized concentration of Ni promote electrocatalytic reactions.