Nitrogen evolution as anodic reaction in molten LiF–CaF2

Abstract

The electrochemical behaviour of nitride ions has been studied in fluoride melts (eutectic LiF-CaF 2) by cyclic voltammetry and square wave voltammetry. The purpose of this work is to propose an alternative way for anodic reaction in molten fluorides processes. Thermodynamical analysis can be used for the evaluation of the anodic material regarding to its oxidation potential and reactivity with nitrogen. Then electrochemical investigations confirm the oxidation of nitride ions into nitrogen in a one-step process exchanging 3 electrons, and let propose several materials usable for nitrogen evolving.

Electrochemical behavior of iodide ions in molten fluoride salts

“…An electroactivity domain of 4.21 V was determined. Cathodic and anodic limits belong to the reduction of lithium ions to lithium metal at -1.68 V vs Pt, and the oxidation of the gold working electrode at +2.53 V vs Pt [28]. The oxidation of oxide ions to oxygen gas was characterized by the presence of an anodic pic at +1.6V vs Pt.…”

“…Then the reaction rate can be rewritten as a function of a pseudo second order rate constant (k') with respect to iodide ions. Finally, the reaction rate can be expressed by equation (28) For both experimental conditions, a kinetic of secondary order was used to simulate the oxidation of the iodide ions in LiF-ThF4, Figure 9. The lineal kinetic relation is written as:…”