在LiCl-KCl-CeCl3熔盐中铝电极上欠电位沉积制备Al-Ce合金

Underpotential Deposition of Al-Ce Alloys at an Al electrode from LiCl-KCl-CeCl3 Melts

摘要:

在843K LiCl-KCl-CeCl3熔盐中活性铝电极上，研究了Ce(III)离子的电化学行为和欠电位沉积Al-Ce合金。对比循环伏安曲线发现，在Al电极上Ce(III)/Ce反应的氧化还原电势比在Mo惰性电极上更正；开路计时电位在金属铝和铈的沉积平台之间出现两个平台，这表明Ce(III)在Al活性电极上可以生成两种金属间化合物。以上结果在电化学机理上说明Ce(III)离子可以在Al电极上欠电位沉积形成金属间化合物。在该实验条件下通过恒电位电解，在Al电极上得到了Al-Ce合金，验证了理论分析的结果。经XRD表征，证实了形成AlCe和AlCe3两种合金；经SEM和EDS表征，证明了铈分布在Al电极表面厚度均一的合金镀层中（厚度28?m）。 关键词：LiCl-KCl熔盐；欠电位沉积；铝电极；Al-Ce合金

Abstract:

Electrochemical behavior of Ce(III) and underpotential deposition of Al-Ce alloys were investigated at an Al active electrode in LiCl-KCl-CeCl3 melts. Compared with the cyclic voltammetry curves on a Mo electrode, the redox potential of Ce(III)/Ce at an Al electrode was more positive; there were two new plateaus between the deposition plateau of Al and Ce metal by circuit chronopotentiometry, which means forming two kinds of intermetallic compound. These results showed Ce(III) forming intermetallic compound due to underpotential deposition by electrochemical theory. Furthermore, these were confirmed by Al-Ce alloys, which were obtained at Al active electrode in LiCl-KCl-CeCl3 melts after potentiostatic deposition under the same condition. The formation of AlCe and AlCe3 were illuminated by X-ray diffraction (XRD). The analysis of scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) showed that cerium exists at the surface of Al electrode to form a layer, which was about 28?m evenly coated the Al electrode.