Morphology-controlled synthesis of highly adsorptive tungsten oxide nanostructures and their application to water treatment

A facile route to control the morphology of tungsten oxide hierarchical hollow structures was demonstrated. The morphology of the tungsten oxide nanostructures could be tuned from size-controlled hollow urchins to nanowires by adjusting the concentration of the tungsten precursor, with no need for catalysts, surfactants, or templates. The tungsten oxide nanostructures were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and nitrogen adsorption-desorption measurements. The as-prepared tungsten oxide hierarchical hollow nanostructures showed a very high specific surface area and demonstrated an excellent ability to remove organic pollutants. The adsorption capability of our tungsten oxide hierarchical hollow nanostructure was much higher than those of previously reported transition metal oxide nanostructures including Mn3O4, Fe2O3, and MnO2 as well as other alternative adsorbents such as MCM-22, fly ash, and red mud. This study provides a simple strategy for template/surfactant-free synthesis of hierarchical hollow nanostructures. Also, the as-prepared products are expected to be new promising materials for environmental remediation.