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

WO3 center dot H2O nanostructures have been prepared through a facile hydrothermal route by controlling their morphology during synthesis. WO3 center dot H2O nanoplates with a thickness of similar to 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 center dot H2O. The formation mechanisms for WO3 center dot H2O nanoplates and WO3 center dot H2O HMSs were investigated. The photocatalytic activities, determined by rhodamine B (RhB) degradation under visible light irradiation of WO3 center dot H2O HMSs photocatalysts, were significantly improved as compared with WO3 center dot H2O nanoplates. The higher efficiency of photocatalytic activity in WO3 center dot H2O HMSs was attributed to its higher surface-to-volume ratio and stability against aggregation. In addition, we investigated the toxicity of WO3 center dot H2O HMSs against an important model fungus, yeast (Saccharomyces cerevisiae). The results indicate that the as-synthesized hierarchical WO3 center dot H2O HMSs could be used as a green and efficient photocatalyst.