Novel raspberry-like hollow SiO2@TiO2 nanocomposites with improved photocatalytic self-cleaning properties: Towards antireflective coatings

Uniform raspberry-like hollow SiO 2 @TiO 2 composite nanospheres (hSiO 2 @TiO 2 ) have been designed and prepared via a colloidal assembly method. Series of characterizations, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy , high resolution transmission electron microscopy, thermogravimetry , and derivative thermogravity, have been carried out to analyze the composition, structure and morphology of the composite. The dispersion of TiO 2 nanoparticles on the outer shell of hollow SiO 2 (hSiO 2 ) nanospheres could be effectively tuned via employing H 2 O 2 as a hydroxyl modifier to repair the Si O bonds of the hSiO 2 . The effects of silanol content of hSiO 2 and the Si/Ti ratios were investigated in detail. This unique structure with refractive index of 1.218 and transmittance over 99% exhibited excellent self-cleaning capability when served as antireflective coatings.