Photocatalytic application of Z-type system

Z-type photocatlytic system, resembling natural photosynthesis, consists of two different photocatalysts and a shuttle redox mediator, involving two-photon excitation process for photocatlysis. One photocatalyst as a photoreduction system offers the reduction sites by conduction band (CB) electrons, and the other photocatalyst as a photooxidation system provides the oxidation sites by valence band (VB) holes. A shuttle redox mediator as an electron conductor transfers the electrons from the CB of the photooxidation system to the VB of the photoreduction system. On the one hand, the separation of photocatalytic reactive sites is advantageous for spatial separation of the electrons and holes, which is beneficial for enhancing the photocatlytic activities. On the other hand, photoreduction system and photooxidation system of different materials effectively inhibit the reverse reaction involvement of photoreductive and photooxidative products. The Z-type photocatlytic system simultaneously possesses a wide light absorption range and strong redox ability.