Enhanced photocatalytic activity of a hollow TiO2–Au–TiO2 sandwich structured nanocomposite

Abstract

Combining TiO₂ photocatalysts with noble metal nanoparticles (NPs) has been deemed an effective method to enhance visible-light-induced photocatalytic activity. Herein, we report that the mesoporous hollow TiO₂–Au–TiO₂ (MHTAT) sandwich structured nanocomposite was synthesized using resorcinol–formaldehyde resin polymer nanospheres as templates, followed by TiO₂ coating, Au NP deposition, and external TiO₂ coating, and then hydrothermal treatment and calcination for post-treatment of template removal. The MHTAT nanocomposites have enhanced visible light harvesting efficiency through their unique hierarchical nanostructure and high surface-to-volume ratio, which are beneficial to enhancing visible photocatalytic performance. The Au NPs were sandwiched between two shells of TiO₂ in the MHTAT nanocomposites, which formed close Schottky contact for electron transfer through the interface between TiO₂ and Au in the photocatalytic reaction. The photocatalytic activity of MHTAT sandwiched nanocomposites was fully demonstrated in degradation reactions of a number of organic compounds under visible light irradiation, suggesting their intriguing potential as effective visible-light-induced photocatalysts.