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Title: Electrochemical studies of oxide ions and related species in molten fluorides

Journal Article · · J. Electrochem. Soc.; (United States)
DOI:https://doi.org/10.1149/1.2133333· OSTI ID:7087550

The electrochemistry of oxide ions was studied in molten LiF-BeF/sub 2/-ZrF/sub 4/ (65.6-29.4-5.0 mole percent (m/o)) and LiF-BeF/sub 2/-ThF/sub 4/ (72-16-12 m/o) at gold, iridium, and glassy carbon electrodes in the temperature interval 500/sup 0/--710/sup 0/C. Well-defined and reproducible voltammograms could be obtained only at gold electrodes. Cyclic voltammetric and chronopotentiometric results indicate the following electrochemical reaction pathway O/sup 2 -/ = O + 2e, O + O = O/sub 2/, and O + O/sup 2 -/ = O/sub 2//sup 2 -/. Some evidence for adsorption of O/sub 2/ was obtained. O/sub 2//sup 2 -/ ions are oxidized further producing a voltammetric postwave which increases with Na/sub 2/O/sub 2/ additions. O/sub 2//sup 2 -/ ions gradually decompose in these media; this decomposition is more rapid in Zr(IV)-containing melts as compared to the Th(IV)-containing melts. NaO/sub 2/ additions result in the same voltammetric results as obtained upon the addition of Na/sub 2/O/sub 2/, indicating that O/sub 2//sup -/ ions are more unstable in these melts than in the previously studied LiF-NaF-KF eutectic. The results obtained provide the basis for an in situ electrochemical determination of small amounts of dissolved oxide.

OSTI ID:
7087550
Journal Information:
J. Electrochem. Soc.; (United States), Vol. 124:4
Country of Publication:
United States
Language:
English