Organosilane-Functionalized Carbon Nanospheres: Synthesis and Visible Light Photocatalytic Activity

Organosilane-functionalized carbon nanospheres (SiCNs) with excellent up- and down-converted photoluminescence properties were prepared by the one-pot solvothermal method in ethylene glycol from citric acid and (3-aminopropyl) triethoxysilane (APTES). The as-prepared SiCNs were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflection spectroscopy (DRS) and photoluminescence spectra (PL). The results indicate that uniform spherical SiCNs with diameter of about 30 similar to 50 nm were synthesized at 180 degrees C for 5 h when the mass proportion of APTES and citric acid is 2.0. The visible-driven photocatalytic activity of SiCNs toward the degradation of methylene blue (MB) was investigated. The photocatalytic mechanism was discussed based on the active species during photocatlytic process. The results show that after 120 min visible light irradiation, the degradation rate of MB reached 99% by using SiCNs. The decomposition rate of MB was still above 96% even after 5 recycling uses, thus SiCNs show high visible light photocatalytic activity and excellent stability.