Room temperature synthesis of K2Mo3O10·3H2O nanowires in minutes

Polyoxometalates have been widely used in the fields of catalysis, analytical chemistry, biochemistry, medicine and synthesis of novel organic–inorganic materials. It is difficult to synthesize pure polymolybdate products from a solution because several kinds of molybdenum-based anions may coexist. As a result, varied acidification methods are commonly used for solution synthesis of polymolybdates. In this paper we report an approach for the synthesis of [001]-oriented K2Mo3O10·3H2O nanowires from an aqueous solution of (NH4)6Mo7O24·4H2O and KCl at low temperatures. The reaction occurs even at temperatures as low as 0 °C, and at 30–90 °C the whole procedure needs only a few minutes. Without any additional acidification treatments, the pH value of the solution is maintained in a narrow range of ± 0.1 between 4.9 and 5.5 during the whole synthesis procedure. The starting pH depends on the reaction temperature. Crystalline structure and purity of the final products have been characterized with x-ray diffraction, electron diffraction and dehydration measurements. This simple and rapid method provides a unique case for studying the growth mechanism of polymolybdate nanostructures, and has a promising potential in the mass production of low-cost, pure-phase polymolybdates for a variety of applications.