K3NbF7's electrochemical characteristics in the NaCl-KCl molten salt system at the Mo electrode

Abstract

To explore the electrochemical behavior of Nb (IV) for form Nb metal, molten salt electrolysis was carried out in an NaCl-KCl melt containing K₃NbF₇ at 750 °C. It was discovered that Nb (IV) reduces in three stages: Nb(IV)➔Nb(III)➔Nb(II)➔Nb，and reduction process of Nb(IV)➔Nb(III) was irreversible process controlled by diffusion mechanism. The instantaneous nucleation of niobium on the molybdenum electrode is observed in the KCl-NaCl-K₃NbF₇ melt, which occurs at a potential of −3.06 V vs. Cl₂/Cl⁻ and a temperature of 750 °C, the niobium metal was deposited on Mo wire cathode by constant potential electrolysis, resulting in a high purity of 98.63 %.