Preparation of a composite photocatalyst with enhanced photocatalytic activity: Smaller TiO2 carried on SiO2 microsphere

In order to improve the photocatalytic activity of nano-TiO2 and achieve its recovery, TiO2/MS-SiO2 photocatalyst is prepared when TiO2 nanoparticles are distributed on the surface of amorphous SiO2 microspheres (MS-SiO2) through sol-gel method, and its composition and morphology structure are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). Besides, the photocatalytic properties are tested and evaluated by degradation efficiency of methyl orange under ultraviolet light. The results show that TiO2 nanoparticles uniformly dispersed on the surface of MS-SiO2 and combined with MS-SiO2 strongly by Ti-O-Si bond, whereas TiO2 is anatase crystal and grain size is about 5 nm. Under ultraviolet light for 90 min, the degradation rate of TiO2/MS-SiO2 for methyl orange reached 100%, which is better than pure TiO2 and P25. In addition, photocatalytic performance remains unchanged in a cyclic experiment. Transmission and separation efficiency of nano-TiO2 photo-generated charge carriers is improved by loading on the surface of MS-SiO2 so that MS-SiO2 can enhance the photocatalytic performance of pure TiO2. Moreover, this fact is illustrated by electron paramagnetic resonance intuitively.