Electrorhemical behavior and solvation analysis of rare earth complexes in ionic liquids media investigated by SECM and Raman spectroscopy

摘要

In this study, the electrochemical behavior of neodymium complexes; Nd(III) in the phosphonium ionic liquid; P_(2225)TFSA triethyl-pentyl-phosphonium bis(trifluoromethylsulfonyl)amide was examined by the voltammetric method using a platinum tip electrode. The diffusional behavior of Nd(III) was certificated to be similar behavior of other rare earth complexes such as Sm. The ideal steady-state approach current of the positive feed back was obtained in Nd(III)/P_(2225)TFSA and the fitted function of this approach curve was determined through mathematical treatment. Moreover, the concentration gradient and the related current distribution using ferrocene redox mediator for the electrodeposition process of Nd(III) were investigated by scanning electrochemical microscopy. This result revealed that the current distribution on the platinum substrate for Nd(III) in P_(2225)TFSA was drastically altered after the electrodeposition of Nd(III). Furthermore, it was revealed the interaction between Nd trivalent ion and free TFSA anion would be relatively strong considering from the solvation number analyzed by Raman spectroscopy.