Site Sensitivity of Interfacial Charge Transfer and Photocatalytic Efficiency in Photocatalysis: Methanol Oxidation on Anatase TiO₂ Nanocrystals

Photocatalytic oxidation of methanol on various anatase TiO 2 nanocrystals was studied by in situ and time‐resolved characterizations and DFT calculations. Surface site and resulting surface adsorbates affect the surface band bending/bulk‐to‐surface charge migration processes and interfacial electronic structure/interfacial charge transfer processes. TiO 2 nanocrystals predominantly enclosed by the {001} facets expose a high density of reactive fourfold‐coordinated Ti sites (Ti 4c ) at which CH 3 OH molecules dissociate to form the CH 3 O adsorbate (CH 3 O(a) Ti4c ). CH 3 O(a) Ti4c localized density of states are almost at the valence band maximum of TiO 2 surface, facilitating the interfacial hole transfer process; CH 3 O(a) Ti4c with a high coverage promotes upward surface band bending, facilitating bulk‐to‐surface hole migration. CH 3 O(a) Ti4c exhibits the highest photocatalytic oxidation rate constant. TiO 2 nanocrystals enclosed by the {001} facets are most active in photocatalytic methanol oxidation.