Efficient and Stable Alkaline Oxygen Evolution on Fe/Co Co-Doped NiSe

Abstract

The slow kinetics of the anodic oxygen evolution reaction (OER) impose a major limitation on overall water electrolysis, creating a demand for highly active catalysts. Transition metal selenides (TMSs) offer favorable electrical conductivity, inexpensive constituents, and adjustable electronic configurations; however, their inherent catalytic activity is still insufficient. In this study, nanorod-like Fe/Co co-doped NiSe (Fe,Co–NiSe) was prepared by hydrothermally forming NiSe and subsequently introducing Fe and Co through a simple soaking treatment. The simultaneous incorporation of Fe and Co effectively tunes the electronic structure of NiSe. Raman measurements performed in situ show that introducing Fe/Co favors the generation of NiOOH-type oxyhydroxide species, thereby enhancing OER activity. 18O-labeling differential electrochemical mass spectrometry confirms that Fe,Co–NiSe follows the conventional adsorbate evolution mechanism. Density functional theory (DFT) analysis further indicates that Fe-induced electronic redistribution at Co sites raises the Co d-band position and reduces the Gibbs energy required for the kinetically limiting *O → *OOH conversion. Consequently, under alkaline conditions, Fe,Co–NiSe reaches 10 mA cm–2 at an overpotential of 229 mV and sustains 50 mA cm–2 for 300 h. When employed as the anodic electrode in an anion exchange membrane (AEM) water electrolyzer coupled with Pt/C, this electrolyzer delivers 1 A cm–2 while registering a cell voltage of 1.84 V.