Controlled fabrication of hierarchical WO3·H2O hollow microspheres for enhanced visible light photocatalysis

Abstract

WO₃·H₂O nanostructures have been prepared through a facile hydrothermal route by controlling their morphology during synthesis. WO₃·H₂O nanoplates with a thickness of ∼45 nm and hierarchical hollow microspheres (HMSs) structures could be obtained by introducing different amounts of citric acid. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to understand the structure and morphology of the two types of WO₃·H₂O. The formation mechanisms for WO₃·H₂O nanoplates and WO₃·H₂O HMSs were investigated. The photocatalytic activities, determined by rhodamine B (RhB) degradation under visible light irradiation of WO₃·H₂O HMSs photocatalysts, were significantly improved as compared with WO₃·H₂O nanoplates. The higher efficiency of photocatalytic activity in WO₃·H₂O HMSs was attributed to its higher surface-to-volume ratio and stability against aggregation. In addition, we investigated the toxicity of WO₃·H₂O HMSs against an important model fungus, yeast (Saccharomyces cerevisiae). The results indicate that the as-synthesized hierarchical WO₃·H₂O HMSs could be used as a green and efficient photocatalyst.