Synthesis of Single-Crystalline Hollow Octahedral NiO

Abstract

We have successfully fabricated single-crystalline hollow NiO crystals with well-defined octahedral morphology. With detailed investigations by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis, we propose a growth mechanism of the hollow octahedra. It is the first report that hollow octahedral materials can be synthesized via a template-assisted carbothermal method. During the process, carbon templates appear to be necessary for the formation of single-crystalline hollow NiO octahedra. The proposed facile strategy can be extended to synthesize other polyhedral materials such as metal oxides (Co3O4, etc.).