Surfactant-free hydrothermal synthesis and characterization of single-crystal K2V8O21 nanobelts

Single-crystal K2V8O21 nanobelts were prepared from the reaction between V2O5 and KHSO4 under hydrothermal condition using no surfactant or template. The synthesized nanobelts were characterized by X-ray diffraction, X-ray photon-electron spectrometry, scanning electron microscopy, and transmission electron microscopy. The nanobelts are single-crystalline in nature, and have typical width of 100–500 nm, thickness of less than 100 nm and length up to a few tens of microns. The effects of solution concentration, reaction temperature and molar ratio of K and V on the morphology and phase component of the obtained products have been investigated. The possible formation mechanism was also discussed.