Direct electrochemical reduction of Dy2O3 in CaCl2 melt

Abstract

The electrochemical reduction of Dy2O3 in CaCl 2 melt was studied. The cyclic voltammetry, chronoamperometry, AC impedance and constant voltage electrolysis were employed. A single cathodic current peak in the cyclic voltammogram and one response semicircle in the AC impedance spectrum were observed, supporting a one-step electrochemical reduction mechanism of Dy2O3. No intermediates were observed by XRD, which confirmed the following electrochemical reduction sequence: Dy2O3 → Dy. The charge transfer resistances and the activation energies involved in the electrochemical reduction step of Dy2O3 were obtained by simulating the AC impedance spectra with equivalent circuits. The electrochemical reduction reaction of Dy 2O3 is controlled by the charge transfer process at a low voltage range and by the diffusion process at a high voltage range. © Springer Science+Business Media B.V. 2012.