Facile synthesis, magnetic and optical properties of double-shelled Co₃O₄ hollow microspheres

Double-shelled Co₃O₄ hollow spheres are successfully synthesized by chemically induced self-assembly in the hydrothermal environment. The morphology, chemical composition, and crystalline structure of the double-shelled Co₃O₄ hollow spheres are characterized by different techniques, such as powder X-ray diffraction (PXRD), Raman spectrum, X-ray photoelectron spectrum (XPS), field emission scanning electron microscope (FESEM), and high resolution transmission electron microscope (HRTEM) with selected area electron diffraction (SAED). Magnetic measurements and optical spectra suggest the double-shelled Co₃O₄ hollow spheres exhibit close to a weak ferromagnetic behaviour and enhanced photogenerated carrier separation. Since this synthetic route is simple, convenient, and "green", it is possible to extend this synthetic method to preparation of a wide range of the multishelled hollow spheres of metal oxides for semiconductor device applications.