Rutile TiO2(011)-2 × 1 Reconstructed Surfaces with Optical Absorption over the Visible Light Spectrum.

The stable structures of the reconstructed rutile TiO2(011) surface are explored based on an evolutionary method. In addition to the well-known "brookite(001)-like" 2 × 1 reconstruction model, three 2 × 1 reconstruction structures are revealed for the first time, all being more stable in the high Ti-rich condition. Importantly, the predicted Ti4O4-2 × 1 surface model not only is in excellent agreement with the reconstructed metastable surface detected by Tao et al. [Nat. Chem. 3, 296 (2011)] from their STM experiment but also gives a consistent formation mechanism and electronic structures with the measured surface. The computed imaginary part of the dielectric function suggests that the newly predicted reconstructed surfaces are capable of optical absorption over the entire visible light spectrum, thereby offering high potential for photocatalytic applications.