Hierarchical WO₃ Hollow Shells: Dendrite, Sphere, Dumbbell, and Their Photocatalytic Properties

In this work, hierarchical WO 3 hollow shells: dendrites, spheres and dumbbells have been successfully synthesized by simply calcining the acid‐treated PbWO 4 and SrWO 4 as precursors at 500 °C for 2 h. These hollow structures were characterized using X‐ray diffraction, scanning and transmission electron microscopies, Brunauer–Emmet–Teller surface area and diffuse reflectance spectroscopy, respectively. Possible formation mechanisms for hollow WO 3 shells consisted of tiny nanoplatelets were investigated in detail. Comparing with commercial WO 3 particles, all the obtained hollow shells with larger BET surface areas showed enhanced photocatalytic activities for the degradation of organic contaminants under visible light irradiation.