Fabrication and photocatalytic properties of spheres-in-spheres ZnO/ZnAl2O4 composite hollow microspheres

ZnO/ZnAl2O4 composite hollow microspheres have been fabricated using glucose as template by a polyethylene glycol (PEG-4000)-assisted one-pot hydrothermal method. The as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis diffusive reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) measurement and X-ray photoelectron spectroscopy (XPS). The effects of the content of ZnO(X) and the molar ratio of glucose to metal ion (R) on the structure, composition, morphology and textural properties of the as-prepared samples were investigated in detail. The results indicated that a novel spheres-in-spheres ZnO/ZnAl2O4 composite hollow microspheres (designated as S@S-ZnO/ZnAl2O4) could be obtained as X = 25 mol% and R = 1. In addition, the photocatalytic activity of the as-prepared samples was evaluated by photocatalytic decolorization of methyl orange (MO) aqueous solution under the irradiation of the simulated sunlight (100 mW/cm2). The maximum photocatalytic decoloration rate of 98.7% within 60 min was obtained at 0.5 g L−1 concentration of S@S-ZnO/ZnAl2O4 photocatalyst, which exceeded that of Degussa P25 under the same conditions.