LiCl熔盐中直接电解还原制备Ce-Ni/Zn/Bi合金

在923K、LiCl熔盐中,通过两电极体系直接电解还原CeO_2-5NiO、CeO_2-2.5Bi_2O_3、CeO_2-5ZnO三种混合氧化物制备相应的金属间化合物。从热力学上计算了3种混合氧化物的理论分解电压,并采用循环伏安法研究其电化学行为,验证了电解还原的可行性。结果表明,3种混合氧化物分别在3.2V被直接电解还原4h,NiO、Bi_2O_3、ZnO均能在CeO_2发生还原反应前生成对应的金属单质,然后促进CeO_2还原。得到的电解产物分别为CeNi_5/Ni、CeBi/Bi、CeZn_5/Ce_3Zn_(22)/CeZn_3。3种电解产物的微观形貌分别为絮状、堆积状和块状。

Direct Electrochemical Preparation of Ce-Ni/Zn/Bi Alloy from Mixture Oxides in LiCl Molten Salt

Intermetallic compounds of Ce-Ni, Ce-Bi and Ce-Zn were prepared from their mixture oxides (CeO2-5NiO, CeO2-2.5Bi2O3 and CeO2-5ZnO) by constant voltage electrolysis in LiCl molten salt at 923 K. In order to verify the feasibility of electrochemical reduction of these oxides, theoretical decomposition voltage was calculated by Standard Gibbs Free Energy, and electrochemical reduction behaviors of these oxides and mixture oxides were investigated by Cyclic Voltammetry (CV) measurement. The results show that electrochemical reductions of NiO, Bi2O3 and ZnO powder at 3.2 V for 4 h can be readily realized at lower voltage, which will facilitate reduction of CeO2 powder with high thermodynamic stability and poor conductivity. Electrolytic product is CeNi5/Ni, CeBi/Bi and CeZn5/Ce3Zn22/CeZn3, respectively. Morphology of electrolytic products is flocculent, accumulative and lumpy, respectively.