Importance of a quasistable V4O9 to synthesize a highly crystalline VOHPO4·0.5H2O Original Research Article

The organic solvent method to synthesize a highly crystalline VOHPO4·0.5H2O was investigated. Firstly, reduction of V2O5 in alcohols was studied. It was clear that there existed a quasistable V4O9 state after reduction with isobutyl alcohol. When a mixture of isobutyl alcohol and benzyl alcohol was used, the reduction was relatively rapid and difficult to control. Secondly, pure, uniform and roseshaped precursor VOHPO4·0.5H2O was obtained by the dehydration-condensation of V4O9 and ortho-H3PO4 when ortho-H3PO4 was added dropwise. The balance in rates between addition of ortho-H3PO4 and the dehydration-condensation was important to prepare a uniform precursor.