Eccentric Corrosion-Induced Formation of γ-NiFeOOH and γ-NiCoOOH on NiFeCo Alloy for Enhanced OER

An indirect, swift, and easy method of enhancing the oxygen evolution reaction (OER) performance of an economically viable Fe-rich NiFeCo (NFC) alloy has been developed. This approach leverages the anodic potential sweeps applied indirectly to the counter electrode (CE) when one does cathodic hydrogen evolution reaction (HER) on by potential sweeping at the working electrode (WE). In this method, NFC was intentionally corroded indirectly by using it as a CE for the potential sweeping HER experiment done with a Pt WE. The indirectly corroded NFC (NFC_IC) featuring mostly γ-NiFeOOH and γ-NiCoOOH entities on the surface was able to begin the OER at an onset overpotential of 250 mV and reach the benchmark of 10 mA cm^-2 at 290 mV, which is 60 and 55 mV lesser than that of the bare NFC and RuO₂, respectively, all with exceptionally faster kinetics, as evidenced by a relatively smaller Tafel slope of 30 mV dec^-1. These insights into designing a trimetallic alloy-based OER electrocatalyst have opened a previously unknown avenue in the development of advanced self-supported OER electrodes for better and efficient H₂ production via water electrolysis.