In photocatalysis, semiconductors absorb photons to generate electron-hole pairs. These charge carriers can migrate to the surface of the semiconductor, where they participate in redox reactions. For instance, in the photocatalytic degradation of pollutants, the electrons can reduce oxygen molecules, while the holes can oxidize water or organic pollutants. Common semiconductor materials used in photocatalysis include titanium dioxide (TiO2), zinc oxide (ZnO), and cadmium sulfide (CdS).
