Synthesis of highly monodispersed teardrop-shaped core–shell SiO2/TiO2 nanoparticles and their photocatalytic activities

Abstract

In this study, teardrop-shaped SiO2/TiO2 nanoparticles (TST-NPs) with core–shell structure were fabricated from tetraethoxysilane (TEOS) and tetrabutyl titanate (TBT) by sol–gel method. And these nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and UV–vis spectroscopy. Photocatalytic activity of teardrop-shaped SiO2/TiO2 nanoparticles after calcination (CST-NPs) was studied towards degradation of methylene blue under sunlight irradiation. The result showed that CST-NPs possessed good photocatalytic activity. The photocatalytic mechanism was also studied by adding different capture agent. Results showed that addition of 0.003M of I− decreased the degradation of MB more than same amount of Ag+, indicating that the photogenerated holes may play a more essential role than photoinjected electrons in the oxidation of MB.