Synergistic Fe,Ce doping of Ni3S2 for enhancing oxygen evolution reaction performance

Abstract

The development of low-cost, efficient, and stable electrocatalysts is critical for the anodic oxygen evolution reaction (OER). Ni₃S₂ not only has the advantages of low cost, easy preparation, and environmental friendliness, but also attracts attention for its structure throughout the Ni–Ni bond, which provides metal-like electrical conductivity. In this work, the Fe and Ce double-doped Ni₃S₂ nanoneedle array catalyst (Fe,Ce-Ni₃S₂@NF) was prepared by a one-step hydrothermal method. The synergistic doping of Fe and Ce optimized the microscopic morphology and the electronic structure of Ni₃S₂, which increased the exposure of catalytically active sites, enhanced the electron transfer rate in the OER process, and improved the intrinsic activity of the catalyst. The catalyst has an overpotential of 254 mV at 10 mA cm⁻² and a Tafel slope of 55.56 mV dec⁻¹, and exhibits good electrocatalytic performance under alkaline conditions (1 M KOH). Compared with the original Ni₃S₂ (363 mV at 10 mA cm⁻²), the overpotential of Fe,Ce-Ni₃S₂@NF is reduced by 109 mV. This provides a new feasible direction for the preparation of transition metal and lanthanide metal double-doped catalysts and their application in electrocatalysis.