Synthesis of 1D to 3D nanostructured NiCo2S4 on nickel foam and their application in oxygen evolution reaction

Design of highly efficient, stable and low-cost water oxidation electrocatalysts continues to be a great impetus and significant challenge for renewable energy systems. In this paper, four diverse morphologies of NiCo₂S₄ including one-dimensional nanoneedles, two-dimensional nanosheets, three-dimensional flower-like and caterpillar-like arrays are direct grown on nickel foam via a facile two-step hydrothermal process. Influences of synthesis conditions on forming process, morphology, constitution and properties are discussed in detail. Results show that caterpillar-like NiCo₂S₄ catalyst displays the best electrocatalytic activity toward oxygen evolution reaction, which only needs an overpotential of 279 mV to deliver a current density of 50 mA·cm⁻² and the Tafel slope is 68 mV/dec in 1 M KOH. Furthermore, caterpillar-like NiCo₂S₄ demonstrates excellent stability with inappreciable change of current density after 20 h of oxygen release. This work provides a wide range of possibilities for the further development of cost-effective high efficient electrocatalyst towards oxygen evolution reaction.