Photocatalysts for solar-induced water disinfection: New developments and opportunities

Recent years have seen a surge of interest in the application of solar energy for water disinfection by using nano-structured photocatalysts elaborately designed and fabricated. Photocatalysis has its unique advantage for utilizing sunlight to drive the disinfection process. The highly reactive oxygen species (ROS) serve as the main oxidants and are capable of inactivating microorganisms, including viruses, bacteria, spores and protozoa. This chapter presents an overview of current research activities that center on the preparation, characterization and application of highly efficient photocatalysts for water disinfection under both UV and visible light irradiation. It is organized into two major parts. One is the development of TiO2-based photocatalysts including surface noble metal modified, ion doped, dye-sensitized, and composite TiO2. The other part is the introduction of new types of photocatalysts and advanced technologies that have recently fascinated the scientific community. Particular attention is given to the pioneering fields such as graphene-based photocatalysts, plasmonic-metal nanostructures and naturally occurring photocatalysts. Finally, we conclude with a discussion of what major advancements are needed to move the field of photocatalytic water disinfection forward.