Preparation of Mo nanopowders through electroreduction of solid MoS2 in molten KCl–NaCl

Abstract

Electrolysis of MoS₂ to produce Mo nanopowders and elemental sulfur has been studied in an equimolar mixture of NaCl and KCl at 700 °C. The reduction mechanism was investigated by cyclic voltammetry (CV), potentiostatic and constant voltage electrolysis together with spectroscopic and scanning electron microscopic analyses. The reduction pathway was identified to be MoS₂ → L_xMoS₂ (x ≤ 1, L = Na or K) → L₃Mo₆S₈ and LMo₃S₃ → Mo, and the last step to format metallic Mo was found to be relatively slow in kinetics. Electrolysis at a cell voltage of 2.7 V has led to a rapid reduction of MoS₂ to nodular Mo nanoparticles (50–100 nm), with the current efficiency and energy consumption being about 92% and 2.07 kW h kg⁻¹-Mo, respectively.