高氯酸介质中ReO^(-)_(4)的电化学行为北大核心CSCD

^(99)Tc是一种长寿命(T_(1/2)=2.13×10^(5)a)裂变产物核素,在后处理PUREX流程走向复杂,是乏燃料后处理中十分关注的核素之一。由于Re与Tc化学行为相似,因此通常用Re作为Tc的替代物进行模拟研究。本工作采用循环伏安法、差分脉冲伏安法和计时电位法对0.5 mol/L HClO_(4)介质中ReO_(4)^(-)的电化学行为进行了研究。研究结果表明,Re的电化学表现为多电子转移过程。在Pt电极上,Re(Ⅶ)易发生3电子转移还原为Re(Ⅳ)的反应,同时存在单电子转移逐步还原为Re(Ⅵ)和Re(Ⅴ)的电化学过程。在还原电位低于0 V,Pt电极上的吸附氢(Pt-H_(ad))能够将Re(Ⅳ)还原到Re(Ⅲ)。在Au电极上,Re(Ⅶ)通过多步骤的电子转移逐步还原至Re(Ⅲ),Re(Ⅲ)可进一步沉积为金属Re。

Electrochemical Behavior of ReO-4 in Perchloric Acid System

⁹⁹Tc, a long-lived(T_1/2=2.13×10⁵ a) nuclide, has a complex routing in PUREX process due to its various oxidation in the reprocessing of the spent nuclear fuel which gets special attention. Rhenium is usually used as a simulant to study the chemical behavior of technetium since they have similar chemical behaviors. The electrochemical behavior of ReO^-₄ in 0.5 mol/L HClO₄ solution was studied by cyclic voltammetry, differential pulse voltammetry and chronopotentiometry. The result shows that there is a multi-step electron transfer process in the electrochemical reaction of rhenium. Re(Ⅶ) is easily reduced to Re(Ⅳ) by three-electron transfer on platinum electrode, on which Re(Ⅶ) can also be gradually reduced to Re(Ⅵ) and Re(Ⅴ) through single electron transfer. When the reduction potential is lower than 0 V, Pt-Had is electrochemically formed on the platinum electrode surface and subsequently reduce Re(Ⅳ) to Re(Ⅲ). In addition, the electrochemical study of rhenium on gold electrode shows that Re(Ⅶ) is gradually reduced to Re(Ⅲ) by multi-step electron transfer and the Re(Ⅲ) can be further deposited as rhenium.