Functionalization of Au/TiO2 Plasmonic Photocatalysts with Pd by Formation of a Core–Shell Structure for Effective Dechlorination of Chlorobenzene under Irradiation of Visible Light

Gold (Au) nanoparticles supported on titania (TiO2) and ceria have been applied to a visible-light-responding plasmonic photocatalyst and functionalization of Au/TiO2 photocatalysts with cocatalysts were achieved by separate loading of Au nanoparticles and cocatalyst nanoparticles without alloying and nanoparticle coagulation. Here we report effectiveness of another functionalization by formation of a core–shell structure in photocatalytic reaction induced by SPR of Au/TiO2. Newly functionalized core–shell gold–palladium particles supported on TiO2 (Au@Pd/TiO2) were successfully prepared by using a two-step photodeposition method, and Au@Pd/TiO2 with a shell thickness of 1.0 nm quantitatively converted chlorobenzene and 2-propanol to benzene and acetone under irradiation of visible light. Thickness control of the Pd shell was very important for both a satisfactory cocatalyst effect and absorption due to SPR of Au nanoparticles. The results of this study provide useful information for design of functionalization of plasmonic photocatalysts by formation of a core–shell structure.