Ni₃S₂ nanostrips@FeNi-NiFe₂O₄ nanoparticles embedded in N-doped carbon microsphere: An improved electrocatalyst for...

The designing and preparing of low-cost and easily available electrocatalyst for oxygen evolution reaction (OER) are crucial for many advanced energy technologies. Herein, the Ni₃S₂ nanostrips@FeNi-NiFe₂O₄ nanoparticles embedded in N-doped carbon (Ni₃S₂@FeNi-NiFe₂O₄/C) microspheres were synthesized as improved electrocatalyst for OER, using a facile heat-treatment method. The optimized Ni₃S₂@FeNi-NiFe₂O₄/C-3 sample exhibits enhanced electrocatalytic activity toward OER performance with an overpotential of 280 mV at 10 mA cm^-2 and a small Tafel slope of 33.9 mV dec^-1. Furthermore, Ni₃S₂@FeNi-NiFe₂O₄/C-3 composite shows good stability in alkaline media. The outstanding electrocatalytic OER performance of composites was attributed due to the synergetic effect between Ni₃S₂ nanostrips and FeNi-NiFe₂O₄ nanoparticles and it is believed that the heterointerfaces between them act as active centers for OER. Additionally, N-doped carbon prevents the aggregation of Ni₃S₂@FeNi-NiFe₂O₄ species and enhances the conductivity of composites during the OER process.