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

A core/shell SiO/TiO 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 microspheres was a prerequisite for subsequent deposition of the TiO shell with a controllable and uniform thickness. The photocatalytic activity of the core/shell SiO/TiO catalyst for decomposition of Orange II in liquid phase was observed to be comparable with that of P25 (a commercial TiO product of Degussa). Experimental data also showed that the SiO/TiO 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