Metal‐free Photocatalysts

Metal‐free photocatalysts such as graphitic carbon nitrides (g‐C 3 N 4 ) or covalent organic frameworks (COFs) are active in the visible light range, which is advantageous compared to high bandgap materials such as TiO 2 . The materials based on abundant elements such as C, N, O, S, and others show good stability, do not suffer from photocorrosion such as CdS, and can be modified by a variety of strategies. This chapter concentrates on three material classes of metal‐free photocatalysts: graphitic carbon nitrides, COFs, and conducting conjugated polymers. For each material structure, important physicochemical features as well as synthesis procedures are discussed. Every materials section ends with applications as photocatalyst for selected reactions such as hydrogen evolution or water splitting, the reduction of CO 2 , the degradation of pollutants, and the constructive synthesis of organic molecules.