The fabrication of V2O3 by using NH4VO3 as vanadium source without extra reductant under sealed condition

NH 3 produced by the thermolysis of NH 4 VO 3 is a good reductant for the fabrication of low valence vanadium oxides . In this study, the thermodynamics of V–O and V–O–NH 3 was analyzed to provide a theoretical basis for the preparation of V 2 O 3 using NH 4 VO 3 . Based on this analysis, the thermolysis processes of NH 4 VO 3 under different conditions (air, nitrogen and sealed atmosphere) were investigated. Compared with the air and nitrogen conditions, the sealed condition fully utilises NH 3 escaping from NH 4 VO 3 and is more suitable for the low-cost fabrication of V 2 O 3. First, the only product of thermolysis under the dynamic air condition was V 2 O 5 due to the high oxygen partial pressure. Second, the fabrication of VO 2 under the static air and nitrogen conditions was feasible with a high temperature (＞625 ​°C). The formation of VO 2 in these conditions is explained by the instability of V 2 O 5 , which decomposed into VO 2 at a temperature higher than 625 ​°C. Finally, under the sealed condition at 700 ​°C, pure V 2 O 3 was obtained and NH 4 VO 3 underwent the following phase transition: NH 4 VO 3 → (NH 4 ) 4 (V 6 O 16 ) → V 4 O 7 → V 3 O 5 →V 2 O 3 .