Among all kinds of green earth and renewable energy projects underway, semiconductor photocatalysis has received wide interest because it provides an easy way to directly utilize the energy of either natural sunlight or artificial indoor illumination. TiO2, the most widely used photocatalyst, due to its wide band gap, can only be activated under UV irradiation, and thus, the development of novel semiconductor photocatalysts makes a significant advancement in photocatalytic functional materials. One of the effective strategies to overcome this shortcoming is photosensitizing these wide band gap semiconductors with narrow band gap semiconductors which have proper energy levels. This method can not only improve the photocatalytic activity, due to increasing visible-light-harvesting efficiency, but also can decrease the recombination of the charge carriers, because the formation of n–n or n–p heterojunctions between the combined semiconductors can induce internal electric fields between them. In this regard, this review presents some unitary, binary, and ternary non-TiO2 photocatalysts used for the degradation for organic pollutants and for water splitting.
Part of the book: Semiconductor Photocatalysis