A Templated Method to Bi2WO6 Hollow Microspheres and Their Conversion to Double-Shell Bi2O3/Bi2WO6 Hollow Microspheres with Improved Photocatalytic Performance

Bi2WO6 hollow microspheres with dimension of ca. 1.5 μm were synthesized via a hydrothermal method using polystyrene particles as the template. The as-prepared Bi2WO6 hollow microspheres can be further transformed to double-shell Bi2O3/Bi2WO6 hollow microspheres. The samples were fully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, N2-sorption Brunauer–Emmett–Teller surface area, UV–vis diffuse-reflectance spectroscopy, and X-ray photoelectron spectroscopy. The as-formed double-shell Bi2O3/Bi2WO6 hollow microspheres exhibit enhanced photocatalytic activity due to the hollow nature and formation of the p–n junction between p-type Bi2O3 and n-type Bi2WO6. The study provides a general and effective method in the fabrication of composition and dimension-tunable composite hollow microspheres with sound heterojunctions that may show a variety of applications.