Synthesis of reduced vanadium oxides in aqueous solutions

Reduction of aqueous sodium and potassium vanadates with aqueous ABH(4), (A = Na and K) at ambient temperatures has been investigated systematically to obtain reduced vanadium oxides. Although the as-prepared samples do not show any discernible diffraction peaks, several binary crystalline oxides such as V-2,O-3,, V3O5,, VO2, and V6O13, as well as ternary oxides such as Na0.33V2O5, K0.23V2O5, and K2V3O8, could be identified after annealing in evacuated sealed silica tubes at 580 degrees C. The volume and concentration of borohydrides as well as the reaction pH are found to influence the nature of the reaction products. Selected area diffraction of the as-prepared samples in transmission electron microscopy (TEM) indicates that they are nanocrystalline.