Pulse polarography of uranyl(VI) in molten LiClKCl eutectic

Abstract The electrochemical characterization of redox couple UO 2 2+ /UO 2 + in LiClKCl eutectic at 450°C has been carried out with normal pulse polarography on Pt, Au, tin oxide and glassy carbon electrodes. Pt and Au electrodes immersed in the melt containing UO 2 2+ result in mixed potential systems, being corroded considerably with the simultaneous reduction of UO 2 2+ at the open potentials. While the latter two electrodes give well-defined, two steps reduction waves; the first one is a reversible, one-electron transfer with E 1 2 = −0.487 ± 0.005 V vs 1M Pt(II)/Pt, and the second wave, whose onset potential largely depends on the kind of electrode, is ascribed to a succeeding one-electron transfer yielding UO 2 deposits. Pulse polarography on GCE, which has the largest nucleation overvoltage among them, was proved suitable for detection of the intermediate UO 2 + .