Development of Plasmonic Photocatalyst by Site-selective Loading of Bimetallic Nanoparticles of Au and Ag on Titanium(IV) Oxide

Morphology-controlled rutile titanium(IV) oxide (TiO2) and anatase TiO2 were prepared by a hydrothermal method and their surfaces were selectively loaded with Au, Ag and AuAg bimetallic nanoparticles (NPs) by photo-deposition in order to obtain visible-light responsive photocatalysts. With the help of local surface plasmon resonance (LSPR) of noble metal NPs, the photocatalytic activity of noble metal-loaded TiO2 under visible-light irradiation was improved compared to that of bare TiO2. The enhancement of LSPR on the photocatalytic activity of rutile TiO2 was larger than that of anatase TiO2 with optimum amount of Au or AuAg. In addition, the reusability (stability) of AuAg-loaded TiO2 was much better than that of Ag-loaded TiO2. Double-beam photoacoustic results confirmed different trap energy level distribution lead to different electron transfer ways, resulting in different oxidizing capabilities and they gave one of important strategies for designing visible-light responsive TiO2.