Facile hydrothermal synthesis of vanadium oxides nanobelts by ethanol reduction of peroxovanadium complexes

V3O7·H2O and VO2(B) nanobelts were successfully synthesized by a one-pot hydrothermal approach using peroxovanadium (V) complexes, ethanol and water as the starting materials. Some parameters, such as the ratio of ethanol/water, the reaction temperature and the reaction time, were briefly discussed to reveal the formation of vanadium oxides nanobelts. It was found that the ethanol was oxidized to aldehyde confirmed by the silver mirror reaction and gas chromatography. V3O7·H2O and VO2(B) nanobelts could be selectively synthesized by controlling the quantity of ethanol. The possible formation mechanism of the synthesis of vanadium oxides nanobelts was proposed. The electrochemical properties of V3O7·H2O and VO2(B) nanobelts were studied, and they exhibited a high initial discharge capacity of 350 mAh/g and 190 mAh/g, respectively. VO2(M) nanobelts were prepared by the irreversible transformation of VO2(B) nanobelts at 700 °C for 2 h under the inert atmosphere. The phase transition properties of VO2(M) nanobelts were investigated by DSC and variable-temperature IR, which revealed that the as-obtained VO2(M) nanobelts could be applied to the optical switching devices.