An innovative process for clean ammonium-free vanadium precipitation and one-step preparation of vanadium dioxide based on hydrothermal enhancement of organic alcohols

As a transition metal oxide, VO₂ has excellent optical and electrical properties and is widely used in many fields. The production of VO₂ by the reduction of NH₄VO₃ and V₂O₅ will inevitably produce ammonia–nitrogen wastewater and NH₃ emission during the production of NH₄VO₃ and V₂O₅, which will cause serious environmental pollution and will increase economic costs. The large-scale and low-cost synthesis of VO₂ still faces great challenges. In this paper, VO₂(B) was successfully prepared by a one-step hydrothermal method using NaVO₃ as the vanadium source and CH₃CH₂OH as the reducing agent, and the optimal conditions for vanadium precipitation are as follows: vanadium concentration = 30 g/L, CH₃CH₂OH dosage = 20 % (percentage of solution volume), initial pH = 1, reaction temperature = 220 °C, reaction time = 12 h. The vanadium precipitation efficiency under the optimal conditions could reach 98.93 %, and the purity of VO₂(B) could reach 98.59 %. The precipitation products were characterized by XRD, TG, FTIR, XPS, and SEM-EDS. The mechanism of VO₂(B) preparation by ethanol reduction was proposed. This process is characterized by green, clean, and high efficiency. At the same time, the vanadium precipitation effect and vanadium precipitation products of various alcohols were studied to provide technical and theoretical support for the preparation of VO₂(B).