Electrochemical Behavior of Sm(III) and Electrodeposition of Samarium from 1-Butyl-1-Methylpyrrolidinium Dicyanamide Ionic Liquid
Abstract
Electrodeposition of rare-earth metals using ionic liquid is considered as a potential alternative to conventional high-temperature molten salt electrolysis. Herein, the electrochemical reduction of samarium(III) at near ambient conditions is investigated using different samarium precursors, namely, triflate (Sm(OTf)3), nitrate (Sm(NO3)3.6H2O) and chloride (SmCl3), in 1-butyl-1-methylpyrrolidinium dicyanamide ([BMP][DCA]) ionic liquid. FT-infrared and Raman spectroscopy analyses of Sm3+/[BMP][DCA] solutions confirm the coordination of Sm3+ species with ?{\left[D{CA}\right]}^{-}$ ion through nitrogen atom. Cyclic voltammetry of Sm3+ at glassy carbon electrode provides evidence of a two-step reduction process in all the systems via Sm3+ to Sm2+ and Sm2+ to Sm0 with peaks observed at similar reduction potentials owing to indifference in samarium(III) chemistries in each medium which is supported by a plausible mechanism. The diffusion coefficient of Sm3+ in [BMP][DCA] was determined to be 3.00 × 10-7, 3.64 × 10-8 and 1.90 × 10-7 cm2.s-1 for Sm(OTf)3, Sm(NO3)3.6H2O and SmCl3 systems, respectively. The electrodeposition of samarium was achieved on nickel and glassy carbon substrates under two different potentials and temperatures. X-ray photoelectron spectroscopy confirms that the samarium electrodeposits are a mixture of metallic and oxide forms.
- Publication:
-
Journal of the Electrochemical Society
- Pub Date:
- February 2022
- DOI:
- 10.1149/1945-7111/ac4f76
- Bibcode:
- 2022JElS..169b2503A
- Keywords:
-
- samarium;
- cyclic voltammetry;
- spectroscopy;
- dicyanamide ionic liquid;
- electrochemical deposition.