Self-template synthesis of hollow ellipsoid Ni-Mn sulfides for supercapacitors, electrocatalytic oxidation of glucose and water treatment.

In this work, we have successfully developed a simple self-template route for preparation of hollow ellipsoid Ni-Mn sulfides. This route involves the synthesis of solid Ni-Mn ellipsoids via a chemical precipitation method. Then, using thioacetamide (TAA) as the sulfur source, the solid Ni-Mn ellipsoids can be easily converted to hollow ellipsoid Ni-Mn sulfides in ethanol via sulfidation reaction. The as-synthesized hollow ellipsoid Ni-Mn sulfides possess large specific surface areas and porous structures. Benefiting from these structural and compositional advantages, the electrochemical performance of the hollow ellipsoid Ni-Mn sulfides is studied. As expected, the hollow ellipsoid Ni-Mn sulfides show a high specific capacitance of 1636.8 F g-1 at 2.0 A g-1 and good cycling stability (only 4.9% loss after 4000 cycles) as electrode materials for supercapacitors. Furthermore, electrocatalytic oxidation of glucose based on the synthesized hollow ellipsoid Ni-Mn sulfides is also performed. The hollow ellipsoid Ni-Mn sulfides present high sensitivity and selectivity, good stability and a low detection limit (0.02 μM). In addition, the as-synthesized hollow ellipsoid Ni-Mn sulfides exhibit good ability to remove the Congo red dyes from water, which gives them potential application in water treatment. The current work makes a major contribution to the design and preparation of hollow metal sulfide structures, as well as their potential applications in supercapacitors, electrocatalytic oxidation of glucose and water treatment.