We report the fabrication of a metal-decorated hybrid nanocomposite with TiO2 encapsulation (Metal/SiO2@TiO2, Metal=Pt or Ru) using a simple surface-modification chemical process. Metal nanoparticles capped with polyvinylpyrrolidone were successfully assembled on functionalized SiO2 via electrostatic interactions, after which a thin layer of TiO2 was coated on the surface by the sol-gel process to avoid agglomeration of the coated silica spheres. Transmission electron microscopy studies confirmed that the metal nanoparticles were uniformly distributed throughout the surface of the SiO2 with a thin layer of TiO2. In addition, X-ray diffraction was employed to ensure the crystal structure of the uniformly coated thin TiO2 layer. Even after calcination at 500 ℃, the structure remained intact, confirming high thermal stability. The photocatalytic activity of the metal-decorated SiO2/TiO2 nanocomposites was evaluated using the H2 evolution reaction. The Metal/SiO2@TiO2 catalysts show the photocatalytic water splitting efficiency for H2 generation (i.e., 0.14% for Pt/SiO2@TiO2 and 0.12% for Ru/SiO2@TiO2), while there is no generation of H2 on the Metal/SiO2 without a coating layer. These results indicate that the anatase crystalline coating layer has good thermal and chemical stability and plays a significant role in photocatalytic H2 production.

Hybrid Nanocomposite H2 Evolution Photocatalytic Activity Anatase Titania Shell