Fig. 3

Electron transfer reactions at photoredox functionalized metal oxide interfaces. A schematic depicting the major electron transfer reactions that occur at functionalized TiO₂ (a) or SnO₂-TiO₂ core-shell (b) interfaces: excitation of the catalyst by a photon (hν), electron injection into the semiconductor (k_inj), back-electron transfer (k_BET), and intermolecular electron transfer (k_IET). The energy levels of the catalyst redox potentials in the ground and excited states (cat⁺/cat and cat⁺/cat*, respectively), the diiodide redox potential (I₂^•–/2I^–), and the conduction bands of TiO₂ and SnO₂ (E_{CB, TiO2} and E_{CB, SnO2}, respectively) are depicted on an approximate relative energy scale