Sustainable One-Step Conversion of Soluble NaVO₃ into CaV₂O₄ through Molten Salt Electrolysis

Abstract

A simple and green route for the preparation of CaV 2 O 4 through one-step incomplete electrochemical reduction of soluble NaVO 3 in CaCl 2 molten salt is proposed. NaVO 3 was found to exist in the form of Ca 2 VO 4 Cl in the molten salt with VO 4 3− as the reactive ion. CaV 2 O 4 possessing a surface carbon layer and rod structure was obtained by adding CaCO 3 during electrolysis. The electrochemical reduction mechanism was also analyzed, and the results indicated that VO 4 3− was incompletely reduced to VO 2 − at about −1.23 V (vs. Ag/AgCl) by a two-electron transfer process. VO 2 − ions then combined with Ca 2+ to form CaV 2 O 4 . Meanwhile, CO 3 2− was reduced to carbon in a two-step process.

Simple and Controllable Preparation of Molybdenum Carbides by One-Step Co-Electrolysis of Na2MoO4 and CO2

“…NaVO 3 or Na 2 CrO 4 . [16][17][18] Interestingly, it is confirmed that VC can be prepared by the co-electrolysis of NaVO 3 and CO 2 . 19 In fact, molybdenum oxysalt, i.e.…”

“…Recently, a novel and green soluble oxysalts electrolysis (SOSE) method is proposed by our group to prepare metal and oxides. 16,17 Typically, metallic V/Cr and V 2 O 3 are obtained from the oxysalts, i.e. NaVO 3 or Na 2 CrO 4 .…”