A New Au-Na Alloy Reference Electrode in a LiF-NaF-KF Eutectic Melt

摘要

Electrode behavior of Au has been investigated by means of cyclic voltammetry in a LiF-NaF-KF eutectic melt at 773 K. Besides the cathodic current peak corresponding to the electrodeposition of alkali metal, a cathodic peak was also observed at 0.45 V (vs. M~+/M, M = alkali metal). According to the result of XRD analysis, the cathodic peak at 0.45 V was confirmed to be due to the formation of Au_2Na alloy phase. Moreover, open circuit potential transient curve was also investigated after potentiostatic electrolysis at 0.3 V. The obtained potential plateau at 0.535 V was confirmed to correspond to the following equilibrium: 2Au + Na~+ + e~- ←→ Au_2Na Since the (Au_2Na+Au) electrode shows a very stable potential, this electrode can be used as a stable reference electrode in LiF-NaF-KF system. Investigations on the main characteristics of this reference electrode, such as reproducibility, stability and reversibility, have shown the excellence of the (Au_2Na+Au) electrode.