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Herein, SiO2-photonic crystal/TiO2 composite film (STF) with multilayer structure was designed and fabricated via self-assembly method and spin coating method. The micro-morphology and optical properties of the STF were characterized by scanning electron microscope (SEM) and UV/Vis/NIR spectrophotometer respectively. The photocatalytic activity of the STF was tested via the degradation rate of rhodamine B. The characterization results indicate that the STF has a regular ordered structure when the amount of ammonia is 3 mL and the concentration of SiO2 suspension is 1%, and SiO2 can be effectively combined with TiO2, so the STF has the best photocatalytic performance. The double-layer SiO2-photonic crystal/TiO2 composite film (DSTF) was further prepared and compared with the single-layer SiO2-photonic crystal/TiO2 composite film (SSTF). The photocatalytic properties of the DSTF are better than that of the SSTF. Finally, the mechanism of STF with enhanced photocatalytic performance is discussed, indicating that photonic crystal can effectively enhance the utilization of light which are near the wavelength of the center band gap, and then improve the photocatalytic performance of the photocatalyst. [ABSTRACT FROM AUTHOR]

SiO2 colloidal spheres were synthesized by St6ber method. In order to enhance surface charge of the SiO2 spheres, they were modified with succinic acid. Scanning electron microscope (SEM) shows that the average size of modified SiO2 spheres is 473 nm, and its distribution standard deviation is less than 5%; Fourier-transform infrared spectra (FT-IR) and X-ray photoelectron spectrometer (XPS) results indicate that one end of succinic acid is chemically bonded to the SiO2 spheres through esterification; Zeta potential of the modified SiO2 spheres in water solution is improved from -53.72 to -67.46 mV, and surface charge density of the modified SiO2 spheres is enhanced from 0.19 to 0.94 μC/cm². SiO2 colloidal crystal was fabricated from aqueous colloidal solution by the vertical deposition method at 40°C and 60% relative humidity. SEM images show that the sample of SiO2 colloidal crystal is face-centered cubic (fcc) structure with its (111) planes parallel to the substrate. Transmission measurement shows the existence of photonic band gap at 1047 nm. [ABSTRACT FROM AUTHOR]