A facile and environmentally friendly chemical route for the synthesis of metastable VO2 nanobelts

Metastable VO₂ nanobelts, designated as VO₂ (B), were successfully fabricated by a facile hydrothermal route in the presence of V₂O₅ and glucose. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), selected area electronic diffraction (SAED), high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) techniques. The main synthesis parameters such as temperature, reaction time and molar ratio of the starting materials have been also discussed. The results showed that pure B phase VO₂ nanobelts with high crystallinity can be prepared easily at 180 °C in 24 h at the molar ratio of V₂O₅:glucose=1:1. Typically, the belt-like products were 0.6-1.2 μm long, 80-150 nm wide and 20-30 nm thick. It is noted that the whole process is free of any harmful reducing reagents and surfactants, and valuable gluconic acid can be formed as the main by-product. From an economic and environmental point of view, the present approach is particularly fit for the synthesis of VO₂ (B) nanobelts on a large scale.