Nanostructured nickel-cobalt oxide and sulfide for applications in supercapacitors and green energy production using waste water

Abstract

Abstract With the advancement in technology, the demand for green energy production and storage is increasing year by year. To meet the increasing demand for green energy, there has been continuous research in a bid to find better materials and efficient ways to store energy. Supercapacitors continue to show a promising green energy storage capacity with their modified and improved electrode materials, which show better electrochemical properties. Transition metals such as Fe, Mo, Ni, etc. based materials have shown great potential for electrode materials in supercapacitors, electrocatalysts for water splitting, and urea oxidation reaction (UOR). In this work, nanostructured nickel‑cobalt oxide and nickel‑cobalt sulfide were synthesized using a facile hydrothermal method for their applications in a supercapacitor, water splitting, and urea oxidation reaction. It was observed that the properties of nickel‑cobalt oxide improved significantly after converting it to nickel‑cobalt sulfide. The energy storage capacity of nickel‑cobalt sulfide was significantly enhanced compared to nickel‑cobalt oxide. Additionally, nickel‑cobalt sulfide showed an overpotential of 282 mV, while nickel‑cobalt oxide displayed an overpotential of 379 mV to generate a current density of 10 mA/cm2, towards oxygen evolution reaction. After the introduction of 0.33 M urea, the potential for oxidation of urea for both nickel‑cobalt oxide and nickel‑cobalt sulfide was reduced significantly.