LAUSR

As a typical photocatalyst, TiO2 has been intensively studied for water splitting. However, the mechanism, especially how photogenerated holes participate in, behind the reaction remains highly debated. It is fundamental to identify the capability of groups at the TiO2/water interface to attract photogenerated holes. In this work, we applied the first-principles many-body Green’s function theory to investigate the behaviors of free photogenerated holes and coupled electron–hole pairs at three kinds of TiO2/water interfaces. Our calculations show that interaction between TiO2 and water elevates their respective valence band edges significantly. The groups derived from water, including Ti–OH, OH–, and H2O, cannot be oxidized by holes from photons at the optical absorption edge of TiO2. With higher-energy UV light, holes may be trapped by Ti–OH and OH–. However, these holes might eventually decay onto three-coordinated lattice O atoms both with and without the presence of photoelectrons if they cannot partic...