Preparation of Multi-Metal Oxide Hollow Sphere Using Layered Double Hydroxide Precursors.

A simple and versatile synthesis method was developed to prepare inorganic multi-metal oxide hollow spheres with tunable compositions. The colloidal nanosheets of layered double hydroxides (LDH) with pre-determined compositions were used as precursors for multi-metal oxides and carbon spheres (CSs) prepared by hydrothermal carbonization of glucose were used as hard templates. Electrostatic force drove the positively charged LDH nanosheets to be anchored by the negatively charged CSs once they were mixed, leading to the formation of core-shell structures. Finally, multi-metal oxides with hollow spherical structures were obtained by calcination. These hollow spheres were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and inductively coupled plasma (ICP). Results revealed that the as-prepared oxide hollow spheres could exactly inherit the metal-to-metal ratios of initial LDH precursors, which provided an effective way to control the compositions of oxide shells. This strategy was suitable for preparation of a series of oxide hollow spheres from binary to multi-component ones, including MgO/Al2O3, MgO/Fe3O4, NiO/Al2O3, and ZnO/NiO/Al2O3. [ABSTRACT FROM AUTHOR]