物理化学学报 >> 2016, Vol. 32 >> Issue (7): 1708-1714.doi: 10.3866/PKU.WHXB201604143

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Pr(Ⅲ)离子在LiCl-KCl熔体中Bi膜W电极上的电化学行为

姜涛1,彭述明1,*(),李梅2,裴婷婷2,韩伟2,*(),孙杨2,张密林2   

  1. 1 中国工程物理研究院核物理与化学研究所,四川绵阳621900
    2 哈尔滨工程大学材料科学与化学工程学院,教育部超轻材料与表面技术重点实验室,哈尔滨150001
  • 收稿日期:2016-02-26 发布日期:2016-07-08
  • 通讯作者: 彭述明,韩伟 E-mail:weihan@hrbeu.edu.cn

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

Tao JIANG1,Shu-Ming PENG1,*(),Mei LI2,Ting-Ting PEI2,Wei HAN2,*(),Yang SUN2,Mi-Lin ZHANG2   

  1. 1 Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province, P. R. China
    2 Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, P. R. China
  • Received:2016-02-26 Published:2016-07-08
  • Contact: Shu-Ming PENG,Wei HAN E-mail:weihan@hrbeu.edu.cn

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摘要：

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LiCl-KCl-BiCl3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PrBi2和PrBi。

关键词: Electrochemical behavior, Pr-Bi intermetallic compound, Underpotential deposition, Thermodynamic property, Potentiostatic electrolysis, 电化学行为, Pr-Bi金属间化合物, 欠电位沉积, 热力学性质, 恒电位电解

Abstract:

The electrochemical behavior of Pr(Ⅲ) ions was studied on a Bi-coatedWelectrode in LiCl-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 LiClcompounds, PrBi2 and PrBi, were obtained.