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

Abstract

Low-cost fabrication and compositional manipulation of electrocatalyst are extremely vital to practical application. In this work, an OER electrode substrate composed solely of NiFe 3 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 Feleached is OER-inactive, whereas the spinel type nickel ferrite NiFe 2 O 4 , 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 (Ni x Fe (1À 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 asprepared OER electrode needs an overpotential of only 266 mV to achieve the current density of 10 mA/cm 2 , and its advantages over all other conventionally prepared counterparts make it more suitable for facile oxygen evolution reaction.

Cation-doped sea-urchin-like MnO2 for electrocatalytic overall water splitting

“…4e, there are characteristic peaks of 528.8 and 530.6 eV in the high-resolution XPS spectra of O 1s, attributed to metal oxide bonds (M-O) and metal hydroxyl bonds (M-O-H), respectively. 44,53,54 Fig. 4c shows the high-resolution XPS spectrum of Al 2p, with no metal aluminum peak displayed in the Al 2p spectrum.…”