Electrochemical Conditioning of Metallurgically Prepared NiFe3 Binary Alloy for Facile Oxygen Evolution Reaction

Abstract

AbstractLow‐cost fabrication and compositional manipulation of electrocatalyst are extremely vital to practical application. In this work, an OER electrode substrate composed solely of NiFe3 binary alloy was metallurgically prepared and was subjected to the electrochemical conditionings including the initial Fe‐leaching in a simple KSCN solution to attain the optimum Ni/Fe ratio, the subsequent LSV polarization to activate the OER‐enhancing species and the final CP‐aging in 1 M KOH solution to stabilize the electrocatalyst. The electrode substrate after being Fe‐leached is OER‐inactive, whereas the spinel type nickel ferrite NiFe2O4, which can be generated by LSV polarization, is considered as the “pre‐catalyst”. The “real‐time catalysts” are actually the Fe‐doped nickel (oxy)hydroxides (NixFe(1−x)OOH), which can be compositionally modulated by in‐situ CP‐aging to accomplish the further enhancement of OER properties. Being binder‐free, self‐supporting and substrate‐rejuvenating, the as‐prepared OER electrode needs an overpotential of only 266 mV to achieve the current density of 10 mA/cm2, and its advantages over all other conventionally prepared counterparts make it more suitable for facile oxygen evolution reaction.