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 system atically to obtain reduced vanadium oxides. Although the as-prepared s amples do not show any discernible diffraction peaks, several binary c rystalline 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 ide ntified after annealing in evacuated sealed silica tubes at 580 degree s C. The volume and concentration of borohydrides as well as the react ion pH are found to influence the nature of the reaction products. Sel ected area diffraction of the as-prepared samples in transmission elec tron microscopy (TEM) indicates that they are nanocrystalline.