Visible-Light Photocatalytic Organic Synthesis: Localized Surface Plasmon Resonance-Driven Oxidation Processes Using Au-TiO2 Nanocoupling Systems

This chapter reviews a newly developed visible-light consisting of gold nanoparticles (NPs) and titanium(IV) oxide (Au/TiO₂), the so-called “plasmonic photocatalyst”. Unlike the hitherto studied semiconductor photocatalysts that are activated by the band gap excitation, the redox ability of the “plasmonic photocatalyst” is induced by the excitation of the localized surface plasmon resonance (LSPR) of Au NPs. Au/TiO₂ with strong and broad visible absorption well matching the solar spectrum is a very promising photocatalyst for the solar chemical transformations. Subsequently to the introduction, Section 2 describes the fundamentals of the “plasmonic photocatalyst” in the following of what the LSPR is, the photo-induced interfacial electron transfer, and coupling between LSPR and interband transition of Au NPs. Section 3 summarizes the Au/TiO₂-photocatalytic oxidation processes as organic synthesis, degradation of organic pollutants and water splitting reported so far. Section 4 deals with the important factors affecting the visible-light activity (support effect, Au particle size effect, and reaction field effect) for the design of highly active “plasmonic photocatalysts”.

Keywords: Conduction band, green technologies, photocatalysis, TiO2 oxidation processes, valence band, UV-light-activity.