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 °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 O2 reduction and O2 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.

► Micrometer Co3O4 materials are prepared via a chemical synthesis combined with calcinations.
► The beadlike materials can be formed after calcinations treatments up to 700 °C.
► The performance for electrochemical O2 reduction and O2 evolution in the air/oxygen electrode is investigated.
► The beadlike Co3O4 material has better catalytic activities with bi-functional properties.