Direct electrochemical preparation of CeCo5 alloy from mixed oxides
(1. College of Chemical Engineering, Hebei United University, Tangshan 063009, China;
2. College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China)
2. College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China)
Abstract: CeCo5 alloy was prepared from the mixture of cobalt oxide (Co3O4) and cerium oxide (CeO2) powders by electro-deoxidation in molten calcium chloride. The effects of the cell voltage and sintering temperature on the electrolysis process were reported. The electro-deoxidation mechanism was investigated by potentiodynamic polarization using a molybdenum cavity electrode in conjunction with characterization of the products from constant voltage electrolysis under different conditions by XRD and SEM. The electrochemical property of CeCo5 alloy was investigated by cyclic voltammetry measurements. The results show that the electro-deoxidation rate increases with increasing the cell voltage and decreasing the sintering temperature. The pure CeCo5 can be prepared by direct electro-deoxidation of mixed CeO2/Co3O4 pellets sintered at 850 °C when the cell voltage of 3.1 V is applied. The electro-deoxidation proceeds by the simultaneous reduction of Co3O4 to Co and reduction of CeO2 to CeOCl, followed by CeOCl reduction on the pre-formed Co to form CeCo5 alloy which shows a good cycling stability.
Key words: electro-deoxidation; CeCo5 alloy; CaCl2 melt; oxides