CHAPTER 7: Kinetic Processes in the Presence of Photogenerated Charge Carriers

To understand the details of photocatalytic reactions, it is essential to reveal the kinetic processes of photogenerated charged carriers in photocatalysts. This chapter gives a compact review of primary processes in photocatalysis. First, the photocatalytic processes is outlined along with the redox energies of molecular oxygen and water in addition to the band energy of TiO₂. The dynamics of photoinduced free carriers, i.e., conduction band electrons and valence band holes to be a trap at the surface, and the decay of the trapped carriers with O₂ and alcohols are described. Then, kinetic processes for the formation of ˙O₂⁻, H₂O₂, and ˙OH at the TiO₂ surface are summarized. Finally, the behaviour of photoinduced electrons and holes is presented for visible light responsive TiO₂ such as Cu(ii) deposited TiO₂, Fe(iii) deposited Ru-doped TiO₂, Pt-complex sensitized TiO₂, and gold-nanoparticle sensitized TiO₂.