Hydrogen-Bond Bridged Water Oxidation on {001} Surfaces of Anatase TiO2

Abstract

To gain an atomic-level understanding of the relationship among the surface structure, the interfacial interaction, and the water oxidation activity on TiO2, we studied the adsorption of water and its photocatalytic oxidation on anatase TiO2 with {101} and {001} exposed surfaces by in situ infrared spectroscopy, kinetic isotope effect studies, and density functional theory (DFT)-based molecular dynamics calculations. Our experimental results demonstrate that the oxidation reaction occurs exclusively on hydrogen-bonded water molecules (via surface hydroxyls) over {001} surface, whereas water molecules coordinated on the {101} surface, which are conventionally assigned to the reactive target for hole transfer, remain unchanged during the irradiation. The theoretical calculations reveal that the selective oxidation of water adsorbed on the {001} surfaces is primarily attributed to the formation of hydrogen bonds, which provides a channel to the rapid hole transfer and facilitates the O–H bond cleavage during...