Enhancing Oxygen-Evolution Reaction in Alkaline Conditions with AnodizedFeNi Alloy

The efficient and durable catalysis of the oxygen-evolution reaction (OER) is crucial for theconversion of energy through the water-splitting process. The OER, which involves the oxidationof water, can provide electrons for reduction reactions of H۲O, CO۲, and N۲, leading to theproduction of valuable compounds. In this study, a FeNi alloy foam with a Ni:Fe ratio of ۱:۱ wasanodized at ۵۰ V in a two-electrode system in a KOH solution (۱.۰ M). The resulting materialwas characterized using various techniques including Raman spectroscopy, diffuse reflectancespectroscopy (DRS), X-ray diffraction (XRD), scanning electron microscopy (SEM), energydispersiveX-ray spectrometry (EDX), transmission electron microscopy (TEM), and high-angleannular dark-field imaging (HAADF)-scanning transmission electron microscopy (STEM). ThisFeNi alloy foam was found to be an efficient and durable electrocatalyst for the OER in a KOHsolution (۱.۰ M). The onset overpotential for the OER, based on extrapolation of the Tafel plot,was ۲۲۵ mV, while the overpotentials for current densities of ۱۰ and ۳۰ mA/cm۲ were observedat ۲۷۰ and ۲۹۰ mV, respectively. Additionally, a low Tafel slope of ۳۸.۰ mV per decade wasobserved for the OER. To investigate the mechanism of the OER, in situ surface-enhancedRaman spectroscopy was employed to detect high-valent Fe and Ni species formed on theelectrode surface.