Preparation of CdO hollow microspheres via H2O2 pre-oxidation

Cadmium oxide (CdO) hollow microspheres were prepared by pre-oxidizing Cd powders and subsequent thermal oxidation under normal atmospheric pressure. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to characterize the microstructures. A layer of Cd(OH)2 shell was formed on the surface of the cadmium core during the pre-oxidation process, and the shell transformed into a dense CdO layer at relatively low temperature, which resulted in the formation of CdO hollow sphere during the thermal oxidation. The growth of hollow sphere was mainly affected by the thickness of pre-oxidized layer (the time of pre-oxidation) and the thermal oxidation temperature.