Photocatalysis: Introduction, Mechanism, and Effective Parameters

The widely investigated heterogeneous photocatalysis offers an environmentally friendly, efficient, and versatile solution for several environmental problems. Among others, the removal of harmful organic pollutants and the generation of H2 via water splitting are well-known and most widely studied applications. The process is based on the charge separation caused by the excitation of semiconductor photocatalyst via photon absorption. Due to the intensive development of material science, in addition to the well-known TiO2 and ZnO, several new semiconductor materials have been designed and synthesized to increase the efficiency of heterogeneous photocatalysis and utilization of solar and/or visible light. This chapter describes the principles and mechanisms of heterogeneous photocatalysis, including the formation of photogenerated charge carriers, the role of different reactive species, and the effect of key parameters on the efficiency.