Iron-Doped NiSe₂ and Its Enhanced Oxygen Evolution Reaction Activity

Doping a third element or external functional components into binary alloy nanostructured catalysts typically significantly enhances their electrocatalytic performance. This study demonstrates that doping nickel selenide (NiSe₂) with approximately $10 \mathrm{a}\mathrm{t}\%$ iron (Fe) is an effective strategy for improving its oxygen evolution reaction (OER) catalytic activity. The resulting Ni_0.9Fe_0.1Se₂ undergoes a structural transformation from its original nanodendritic morphology and exhibits outstanding OER catalytic performance in alkaline media. It achieves a low overpotential of $231 \mathrm{m}\mathrm{V}$ at a current density of $10 \mathrm{m}\mathrm{A} {\mathrm{c}\mathrm{m}}^{-2}$, which is approximately $30\%$ lower than that of NiSe₂ ($301 \mathrm{m}\mathrm{V}$). The Tafel slope of Ni_0.9Fe_0.1Se₂ is $116 \mathrm{m}\mathrm{V} {\mathrm{d}\mathrm{e}\mathrm{c}}^{-1}$. However, degradation observed after 5 h of stability testing suggests that the doping process requires further optimization.