Low-temperature template-free synthesis of Cu2O hollow spheres

Cuprous oxide (Cu2O) hollow spheres have been successfully prepared via a template-free hydrothermal method with the assistance of poly(vinylprrolidone) (PVP) at 90 °C. The structure and morphology of the Cu2O hollow spheres were characterized by X-ray diffraction, field-emission scanning electron microscope, and transmission electron microscope. The as-prepared hollow spheres are cubic phase Cu2O. The as-prepared products have a hollow sphere structure with outer diameters of 400–700 nm and the thickness of shells is about 40–70 nm. Poly(vinylprrolidone) is employed for the first time to improve the stabilization of crystalline phase occurred at a rate commensurate with localized Ostwald ripening and self-transformation for producing Cu2O hollow spheres. A possible PVP-assisted Ostwald ripening process is proposed for the formation of Cu2O hollow spheres on the basis of intermediate products at different growth stages.