16. Plasmonic Photocatalysts: Preparation and Evaluation

Colloidal gold (Au) nanoparticles have attracted much attention due to their bright and fascinating color. They show wine-red color and are mostly used in stained glass windows of cathedrals and churches. An absorption band results when the incident photon frequency is resonant with the collective oscillation of the conduction band electrons and is known as surface plasmon resonance (SPR). Recently, plasmonic metal nanoparticles have been applied not only to stained glass but also to chemical sensors and biosensors, surface-enhanced Raman scattering (SERS), fluorescence enhancement, and photocurrent enhancement in photovoltaic cells. More recently, the SPR of Au nanoparticles has been applied to a visible light-responding photocatalyst. In most of the cases, samples were prepared by photodeposition method and there are few papers reporting another method for preparation of plasmonic photocatalysts. In this chapter, we introduce some methods for preparation of gold plasmonic photocatalysts and results of photoinduced chemical reactions over the prepared samples under irradiation of visible light.