Electrochemical properties of Ln(III) (Ln = Ce, Gd) in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

Electrochemical behaviors of Ln(III) (Ln = Ce, Gd) in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid were investigated by cyclic voltammetry and chronopotentiometry. The cyclic voltammograms revealed two electrochemical steps of Ln(III) to Ln(II) followed by Ln(II) to Ln metal. The diffusion coefficients for Ln(III) and Ln(II) were determined to be in order of ∼ 10^-8 cm/s in the temperature range 343 to 373 K. The activation energies for diffusion were 32.17 kJ mol^-1 for Ce(III) and 53.99 kJ mol^-1 for Gd(III). The rate constants of charge transfer obtained by different methods were in a good agreement altogether. The deposits were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. (author)