A Self-Supporting Electrode Material (NiS/NF) as a Stable and Efficient Electrocatalyst for Oxygen Evolution: In Situ Surface Activation of Nickel Sulfide to Nickel Oxide/(Oxy)hydroxide

Binder-free nickel sulfide material grown on NF (NiS/NF) by a basic thermal sulfur growth mechanic was employed as both the electrode material and electrode substrate for water oxidation in 1.0 M KOH. In NiS/NF, sulfur was found to be an activator to transform nickel sulfide to nickel oxide/(oxy)hydroxide. A transmission electron microscopy image of NiS/NF inferred that the oxide/(oxy)hydroxyl layer was found to be amorphous in nature. The energized NiS/NF electrocatalyst showed superior activity in oxygen evolution (OER) at 1.0 M KOH with a minimum overpotential (η) of 290 mV @ 10 mA cm−2. Moreover, a water-splitting device was fabricated by using a photovoltaic solar panel to split water at 1.54 V. Our observation could offer important insight into metal-chalcogenide (M-S) electrocatalysts for low-cost oxygen evolution.