ABSTRACT
This chapter introduces the major principles and theories of photocatalysis and summarizes the latest advances in the field of photocatalytic disinfection. It focuses on the most advances in the field that have not been addressed by the general review articles. The chapter aims to define the process of chemical reactions that take place on the surface of a semiconductor in the presence of a certain range of radiation. The ability of a semiconductor to undergo photocatalytic oxidation is governed by the band energy positions of the semiconductor and redox potentials of the acceptor species. The major reason for the lack of photocatalytic activity in the other compounds is the electronic structure, which for the brookite, columbite, baddeleyite, fluourite, pyrite, and cotunnite has an indirect gap. The structure of the other phases results in an indirect band gap and that is the reason that only rutile and anatase display photocatalytic activity.
