Flower-Shaped NiCo₂S₄ Microspheres for Electrochemical Oxygen Evolution Reaction

Due to fossil fuel depletion and increasing pollution, researchers are now finding ways to develop alternative fuels. Recently, hydrogen became the most focused alternative that can act as a future fuel. Electrochemical water splitting is the cleanest method of producing oxygen and hydrogen from water. Costly noble metal-based materials are used for water splitting and oxygen generation, so there is a strong need to replace platinum with non-precious materials for water splitting. The morphology of the material has a considerable impact on its physical properties and performance. In this research work, we have synthesized flower-shaped nickel cobalt sulfide (NCS-AA) material via a facile hydrothermal method. The material was characterized using SEM and EDS for morphology observation and elemental analysis. The SEM results showed the formation of a flower-type morphology with a diameter of 500 nm to 2 µm and EDS analysis confirmed the presence of Ni, Co, and S. Further, electrochemical analysis was carried out to analyze its performance in oxygen evolution reaction (OER) by performing CV, LSV, and CA analysis techniques. NCS-AA demonstrated good OER activity with an overpotential of ~ 320 mV and a Tafel slope of 115 mV/dec versus a reversible hydrogen electrode for 10 mA/cm² current density. Further, the stability of NCS-AA materials at 50 mA/cm² and 200 mA/cm² was excellent as examined using the chronopotentiometry technique.