Electronic structure: From basic principles to photocatalysis

Abstract In this chapter, we report on research done on dual and multiple photocatalysis by different composites with a two-dimensional nature. Understanding the physics of semiconductors is of great importance to know how to use them as photocatalyst agents. Indeed, the fundamentals of semiconductors are based on the understanding of gap energy states and transport mechanisms as well as the concepts of optical absorption, combination and doping, junctions, and optoelectronic device processes. The high visible light absorption and gradient band structure of the ternary photocatalysts promoted the photogeneration of charges and the following separation of electrons and holes on different compositions. This ternary composite photocatalyst exhibited enhanced photocatalytic performance for the photodegradation of environmental pollution under visible light irradiation compared with single phase as well as their dual composites. This ternary photocatalysis showed superior reusability, and also superoxide radicals were determined as the main active species. The plasmonic ternary hybrid photocatalysts were synthetized and used in water splitting to generate H2 under visible light irradiation.