Ce(Ⅳ)/Ce(Ⅲ)电对在甲基磺酸体系中还原动力学的研究  

Reduction Kinetic of Ce(Ⅳ)/Ce(Ⅲ) Couple in Methanesulfonic Acid

作　　者：陈云扬[1] 周德璧[1] 温美盛[1] 陈芳[1] 谭龙辉[1] 蒋建红[1] 

机构地区：[1]中南大学化学化工学院,湖南长沙410083

出　　处：《中国稀土学报》2010年第6期665-670,共6页Journal of the Chinese Society of Rare Earths

摘　　要：采用循环伏安、极化曲线、交流阻抗等方法对甲基磺酸体系中Ce(Ⅳ)/Ce(Ⅲ)电对在Pt电极上的反应机制和Ce(Ⅳ)还原反应的动力学进行了研究。极化曲线分析表明,Ce(Ⅳ)还原反应是单电子过程,在低过电位下电荷传递电阻为129.1Ω.cm2。循环伏安结果显示:Ce(Ⅳ)/Ce(Ⅲ)电对在Pt电极上的反应是准可逆过程,计算得到Ce(Ⅳ)的扩散系数Dc为5.89×10-6cm2.s-1,标准速率常数k0=3.06×10-4cm.s-1。交流阻抗图谱表明,Ce(Ⅳ)在电解液中的扩散是制约电极反应速率的重要因素。The reaction mechanism and the reduction kinetics of the Ce（Ⅳ）/Ce（Ⅲ） couple in methanesulfonic acid on platinum electrode were investigated by means of cyclic voltammetry,polarization curve and impedance spectroscopies.The polarization curve analysis showed that,the reaction was a single-electron process,and the charge transfer resistance in the low overpotential was 129.1 Ω·cm2.The cyclic voltammetry analysis indicated that Ce（Ⅳ）/Ce（Ⅲ） redox reaction was quasi reversible.The diffusion coefficient for Ce（Ⅳ） was 5.89×10-6 cm2·s-1 and the standard rate constant was 3.06×10-4 cm·s-1.The impedance spectroscopies concluded that the diffusion of Ce（Ⅳ） was the major factor to constrain the electrode reaction rate.

关 键 词：甲基磺酸 Ce(Ⅳ)/Ce(Ⅲ) 动力学 稀土 

分 类 号：O646[理学—物理化学]