Facile synthesis of hierarchical double-shell WO3 microspheres with enhanced photocatalytic activity

Hierarchical double-shell WO3 microspheres (HDS-WO3) have been successfully obtained through the thermal decomposition of WO3·H2O formed by metal salts as the templates. The products were characterized by X-ray diffraction (XRD), and the morphology was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the HDS-WO3 microspheres were analyzed by the Thermogravimetric (TG) and Brunauer-Emmett-Teller (BET) analysis. The synthetic mechanism of the products with hierarchical structures was proposed. The obtained HDS-WO3 exhibits excellent photocatalytic efficiency (84.9%), which is much higher than other WO3 sample under visible light illumination.