A New Route for The Synthesis of Reduced Transition Metal Oxides Using Borohydrides

Abstract

ABSTRACTReduction of aqueous solutions of tungstates, molybdates or vanadates by aqueous alkali metal borohydrides at ambient‐temperature results in a formation of dark colored gel. The gel is amorphous to X‐ray diffraction and crystallizes sharply at around 300‐500 °C to yield reduced transition metal oxides such as the oxide bronzes, NaxMyOz, or the binary oxides, MO2 (M = V, Mo or W). The nature and composition of the products formed are strongly influenced by the reaction conditions such as the reaction pH as well as the concentration and amount of the reagents. Experimental procedures to obtain the different phases are presented. This novel low‐temperature approach has a potential to access new metastable phases.