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

V 3 O 7 ·H 2 O and VO 2 (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. V 3 O 7 ·H 2 O and VO 2 (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 V 3 O 7 ·H 2 O and VO 2 (B) nanobelts were studied, and they exhibited a high initial discharge capacity of 350 mAh/g and 190 mAh/g, respectively. VO 2 (M) nanobelts were prepared by the irreversible transformation of VO 2 (B) nanobelts at 700 °C for 2 h under the inert atmosphere. The phase transition properties of VO 2 (M) nanobelts were investigated by DSC and variable-temperature IR, which revealed that the as-obtained VO 2 (M) nanobelts could be applied to the optical switching devices.