Synthesis of rod and beadlike Co3O4 and bi-functional properties as air/oxygen electrode materials

In this paper, micrometer Co3O4 materials are synthesized via a method of chemical synthesis in combination with calcinations. The effect of calcination temperature on the morphology, structure and catalytic performance as air/oxygen electrode materials are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy and electrochemical techniques. The SEM observation reveals that the morphology of the Co3O4 products changes to a beadlike shape from the rod shape after calcinated at temperature of 700 degrees C. The XRD measurements show that the both morphology Co3O4 products exhibit a cubic phase of Co3O4 spinel with a space group of Fd3m. But the beadlike Co3O4 product has better crystallinity. The electrochemical measurements show that the beadlike Co3O4 material has better active properties for electrochemical O-2 reduction and O-2 generation reactions. Also it exhibits the bi-functional performance in the oxygen-diffusion electrodes and has potential applications in rechargeable metal-air batteries and regenerative fuel cells. (C) 2012 Elsevier Ltd. All rights reserved.