Sulfate salt assistant fabrication of Fe-doped Ni₂P modified with SO₄^2-/carbon as highly efficient oxygen evolution...

The incorporation of oxyanion groups offers a greater potential for enhancing the activity of oxygen evolution reaction (OER) electrocatalysts compared to traditional metal cations doping, owing to their unique configurations and high electronegativity. However, the incorporation of oxyanion groups that differ from those derived from the oxidation of anions in transition metal monoxides poses significant challenges, thereby limiting further applications of oxyanion group modification approach. Herein, we present a novel sulfate salt assistant approach to fabricate Fe-doped Ni₂P modified with SO₄^2-/carbon (Fe-Ni₂P-S/C) nanofibers as highly efficient OER electrocatalyst. The optimized Fe-Ni₂P-S/C nanofibers display superb OER activity, requiring low overpotentials of 266, 323, and 357 mV at 100, 500, and 1000 mA cm^-2, respectively. Theoretical calculations reveal that the co-adsorption of PO₄^3- and SO₄^2- on the surface of reconstructed electrocatalyst can reduce the energy barrier of rate-determining step, thereby resulting in enhanced OER activity. The present study emphasizes the crucial role played by anion groups in OER activity as well as proposes a novel approach for incorporating anion groups into electrocatalysts.