Template-free Hydrothermal Synthesis of CuO/Cu2O Composite Hollow Microspheres

CuO/Cu 2 O composite hollow microspheres with controlled diameter and composition were prepared without the addition of templates and additives by hydrothermal synthesis using Cu(CH 3 COO) 2 ·H 2 O as a precursor. Increasing the precursor concentration from 0.02 to 0.2 M increased the diameter of the composite hollow microspheres from 500 nm to 5 μm. Moreover, the content of Cu 2 O in the composite hollow microspheres increased with increasing the reaction time or/and precursor concentration to produce a range of composite hollow microspheres with Cu 2 O contents from 20 to 80 wt %. A localized Ostwald ripening mechanism was proposed to account for the formation of CuO/Cu 2 O composite hollow microspheres. The photocatalytic activity experiment indicated that the prepared CuO/Cu 2 O composite hollow microspheres exhibited a higher photocatalytic activity for the photocatalytic decolorization of methyl orange aqueous solution under the visible-light illumination than the single phase CuO or Cu 2 O samples.