Fundamentals and Applications of Gold Nanoparticle-Based Plasmonic Photocatalysts for Water Purification

Plasmonic photocatalysts consisting of gold nanoparticles (NPs) and stable metal oxide semiconductors (Au/MOs) represented by Au/TiO2 are very promising materials for solar-driven water purification due to the possible mineralization of organic pollutants. This critical review highlights recent progress of the Au/MO plasmonic photocatalysts for water purification with an emphasis on the fundamentals of the Au NP-based plasmonic photocatalysts to provide readers with material design guidance. First, the degradation mechanism of organic pollutants by the Au/MO plasmonic photocatalysts is explained by comparing it with that of the conventional semiconductor photocatalytic process. Second, the optical, adsorption, and redox properties of Au NP-based plasmonic photocatalysts are discussed with their stability and the others. Third, methods for preparing Au/MOs are described. Fourth, some cutting-edge research relating to the effects of Au particle size and MO support on the plasmonic photocatalytic activity for water purification is described. Particularly, we show the importance of crystallographic control of the Au-MO interface and decoupling of the Au NP actions as photosensitizers and electrocatalysts for the oxygen reduction reaction. Finally, conclusions and some future challenges are summarized.