Characterizations of Nb-doped WO3 nanomaterials and their enhanced photocatalytic performance

In this paper, Nb-doped WO3 nanowires were successfully prepared using a low-temperature, hydrothermal method. The physicochemical properties of pristine and Nb-doped WO3 were determined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy (UV-vis). The photocatalytic properties of those Nb-doped WO3 nanomaterials are evaluated on the basis of their ability to degrade methylene blue (MB) in an aqueous solution under simulated sunlight irradiation. It is demonstrated that the pristine nanowires tend to aggregate, whereas the energy band gap of those nanomaterials narrows as more niobium ions are doped. The photocatalytic experimental results indicated that the Nb-doped WO3 exhibited superior photocatalytic activities to that of the undoped WO3. The Nb-doped WO3 nanowires synthesized with an Nb/W molar ratio of 0.03 possessed the most effective photocatalytic activity among the tested samples.