Synthesis Of Hollow Metal Oxides Spheres And Its Electrochemical Properties Study

Colloidal carbon spheres with hydrophilic surfaces had been successfully synthesized by a hydrothermal route. The diameter of these spheres could be readily tuned over a broad range by controlling the growth parameters such as the reaction time. Under hydrothermal conditions, these carbon spheres could be used as templates for the preparation of hollow metal oxides spheres. With this approach, various of hollow meal oxide spheres could be obtained, and this was proven for several metal salts, among them nickel, managnese, cobalt and iron salts.With the addition of HAuCl4 solution to glucose solution, carbon spheres encapsulating Au nanoparticles could be produced by the same hydrothermal route. Using these hybrid carbon spheres as templates, hollow metal oxides spheres with functionalized interiors and adjustable shell compositions could be fabricated.Hollow and ball-in-ball metal oxide microspheres could also be obtained using a novel stepwise hydrothermal approach. The final product showed spherical hollow structures containing a smaller hollow sphere in their cavities.The NiO products were than used as active electrode material and their electrochemical properties were evaluated in 1M KOH electrolyte solution. The electrochemical capacitance performance of these unique structural NiO was preliminary investigated by the means of cyclic voltammetry (CV) and galvanostatic charge–discharge tests. In the range of 0.0-0.5V, the specific capacitance were 300 F/g and 320 F/g for interior-functionalized NiO hollow spheres and hollow and ball-in-ball NiO spheres, respectively.