Coating of TiO2 Thin Films on the Surface of SiO2 Microspheres: Toward Industrial Photocatalysis

A core/shell SiO 2 /TiO 2 photocatalyst was prepared using a liquid-phase deposition (LPD) method. Zeta-potential measurement showed that deposition of a layer of polyelectrolyte on the surface of SiO 2 microspheres was a prerequisite for subsequent deposition of the TiO 2 shell with a controllable and uniform thickness. The photocatalytic activity of the core/shell SiO 2 /TiO 2 catalyst for decomposition of Orange II in liquid phase was observed to be comparable with that of P25 (a commercial TiO 2 product of Degussa). Experimental data also showed that the SiO 2 /TiO 2 core/shell nanostructured photocatalyst can be easily separated from the reaction medium by sedimentation, and the solid can be recycled and reused. Thus, the photocatalyst described in this work represents a new catalyst system with a high potential for practical applications in treating wastewater.