Morphology-controlled synthesis of WO2.72 nanostructures and their photocatalytic properties

Abstract

The morphologies of nanomaterials have great influence on their properties. In this work, we used the solvothermal method to prepare tungsten oxides with two different morphologies: WO_2.72 nanowires and urchin-like WO_2.72 nanostructures. The photocatalytic activities of these two bare WO_2.72 nanostuctures were evaluated by their efficiency in the degradation of pollutants, during which the influence of the morphology was taken into account. In the experiments, material structures and oxygen vacancies were altered with the change of the morphology. One-dimensional WO_2.72 nanowires with fewer oxygen vacancies showed higher photocatalytic activity than three-dimensional urchin-like WO_2.72 nanostructures with more oxygen vacancies. Thus, we ascertained the prominent role of the structure, rather than the number of oxygen vacancies, in enhancing photocatalytic activity. Surface photocurrent (SPC) measurements further confirmed that WO_2.72 nanowires were more conducive to photo electron transfer than urchin-like WO_2.72 nanostructures, which corresponded with the results of photocatalysis. Compared with commercial nanostructured tungsten oxide, both the WO_2.72 nanowires and urchin-like WO_2.72 nanostructures exhibited enhanced photocatalytic activities for the degradation of pollutants under UV light irradiation.