Synthesis of Highly Monodispersed CdS/SiO2 Core-Shell Nanoparticles and Their Photocatalytic Activities

Monodispersed CdS/SiO2 core-shell composite nanoparticles with effective photocatalytic activity were successfully synthesized. The structure and morphologies of composite nanoparticles were characterized by XRD, FTIR, TEM, and high-resolution transmission electron microscopy (HRTEM). Results showed that the CdS/SiO2 composite nanoparticles exhibited obvious core-shell structure, and that the thickness of the SiO2 shell could be reduced by either increasing the water/alcohol volume ratio or decreasing TEOS amount. The photocatalytic activity of the prepared composite nanoparticles was determined by degradation of methylene blue (MB) in aqueous solution. CdS/SiO2 showed a lower photocatalytic activity compared with CdS nanoparticles. However, the residual concentration of Cd2+ in aqueous solution after MB complete degradation was reduced by half.