Pr(III)离子在LiCl-KCl熔体中Bi膜W电极上的电化学行为（英文）

Electrochemical Behavior of Pr(III) Ions on a Bi-Coated W Electrode in LiCl-KCl Melts

采用循环伏安、方波伏安、计时电位和开路计时电位等电化学方法研究了Pr(III)离子在Li Cl-KCl-Bi Cl_3熔体中W电极上的电化学行为。循环伏安和方波伏安的研究表明,Pr在预先沉积的Bi膜电极上发生欠电位沉积是由于生成了Pr-Bi金属间化合物,导致Pr(III)在Bi膜电极上的还原电位比在W电极上还原电位更正。从开路计时电位曲线可以观察到两相共存的Pr-Bi金属间化合物的两个平台。利用开路计时电位计算了723-873 K温度范围内Pr在Pr-Bi合金中的活度和偏摩尔Gibbs自由能以及Pr-Bi金属间化合物的生成Gibbs自由能。通过恒电位电解,在液态Bi电极上得到了Pr-Bi合金,并采用X射线衍射(XRD)和扫描电子显微镜(SEM)附带能量散射谱(EDS)对样品进行了表征,结果表明所得到的Pr-Bi金属间化合物为Pr Bi_2和Pr Bi。

The electrochemical behavior of Pr（III） ions was studied on a Bi-coated W electrode in Li Cl-KCl melts by a series of techniques, such as cyclic voltammetry, square wave voltammetry, and open circuit chronopotentiometry. From the cyclic voltammogram and square wave voltammogram, the underpotential deposition of Pr（III） on pre-deposited Bi（i.e., a Bi-coated W electrode） occurs, owing to the formation of Pr-Bi intermetallic compounds, resulting in the electrochemical reduction of Pr（III） at less cathodic potentials than that on an inert W electrode. Using the open circuit chronopotentiometry technique, two plateaus, corresponding to the co-existence of two phases of Pr-Bi intermetallic compound, were observed. Thermodynamic properties,such as the activities and relative partial molar Gibbs energies of Pr in the Pr-Bi alloys as well as Gibbs energies of the formation for the Pr- Bi intermetallic compounds, were estimated from the open circuit potential measurement in the temperature range of 723-873 K. Pr-Bi alloys were produced on the liquid Bi pool electrode by potentiostatic electrolysis, and were characterized by X- ray diffraction（XRD） and scanning electronic microscopy with energy- dispersive spectrometry（SEM- EDS）. The results indicated that the intermetallic compounds, Pr Bi2 and Pr Bi, were obtained.