VO₂(B) conversion to VO₂(A) and VO₂(M) and their oxidation resistance and optical switching properties

Vanadium dioxide VO₂ has been paid in recent years increasing attention because of its various applications, however, its oxidation resistance properties in air atmosphere have rarely been reported. Herein, VO₂(B) nanobelts were transformed into VO₂(A) and VO₂(M) nanobelts by hydrothermal route and calcination treatment, respectively. Then, we comparatively studied the oxidation resistance properties of VO₂(B), VO₂(A) and VO₂(M) nanobelts in air atmosphere by thermo-gravimetric analysis and differential thermal analysis (TGA/DTA). It was found that the nanobelts had good thermal stability and oxidation resistance below 341 °C, 408 °C and 465 °C in air, respectively, indicating that they were stable in air at room temperature. The fierce oxidation of the nanobelts occurred at 426, 507 and 645 °C, respectively. The results showed that the VO₂(M) nanobelts had the best thermal stability and oxidation resistance among the others. Furthermore, the phase transition temperatures and optical switching properties of VO₂(A) and VO₂(M) were studied by differential scanning calorimetry (DSC) and variable temperature infrared spectra. It was found that the VO₂(A) and VO₂(M) nanobelts had outstanding thermochromic character and optical switching properties.