In the work, we report a facile template-free approach to prepare hollow VO2 microspheres. Uniform hollow VO2 assemblies composed of ordered microspheres with an average diameter of 3.0 µm and a hollow interior of 2.0 µm were prepared by calcining the precursor, which was synthesized via heat preservation process sealed in Teflon-lined stainless autoclave in the presence of urea. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scan electron microscopy (SEM) have been used to characterize VO2 microspheres. The proposed mechanism for the formation of hollow VO2 microspheres is discussed.

VO2(R) nanobelts were prepared by the irreversible transformation of VO2(B) nanobelts at the elevated temperature. The morphology and size of the VO2(R) nanobelts were dependent on that of the precursor. VO2(B) nanobelts were synthesized by a hydrothermal route, and the process of the VO2(B) nanobelts' formation was also discussed. The product was characterized by a combination of techniques including XRD, TEM, FE-SEM, HRTEM, DTA and FT-IR. The as-obtained VO2(R) nanobelts have a monoclinic structure with a length of 350–600 nm, a wideness of 100–150 nm and a thickness of 20–30 nm.

Well-dispersed Pd nanoparticles were prepared on the surface of vanadium oxide nanotubes (VOx-NTs) through a simple reductive process. The morphology and structure of the resulting Pd/VOx-NTs composites were characterized by transmission electron microscopy (TEM), electron diffraction (ED) and X-ray diffraction (XRD), the results showed Pd nanoparticles were well dispersed with the size distribution from 7 to 13 nm. The electrocatalytic properties of Pd/VOx-NTs composites for methanol oxidation were investigated on the corresponding modified glassy carbon (GC) electrode in alkaline solution. The results indicated the prepared Pd/VOx-NTs composites had an excellent electrocatalytic activity and stability.

A novel and convenient reduction–hydrolysis method was developed to make high-purity VO2 nanopowders. The products have been studied with XRD, IR, XPS, and DTA. The nanopowders exhibited a strong crystallographic transition to the rutile-type structure around 68–72 °C. The XRD patterns and TEM images of products showed that the average size of samples was in the range of 30–40 nm. The XPS results demonstrated that the vanadium exists as V4+ ions in the products. We also found that the phase transition temperature of products decreased by tungsten doping.