We use density functional theory (DFT) calculations to investigate structural models consisting of anatase TiO2(101) slabs covered by reduced overlayers formed by (101) crystallographic shear planes (CSPs). Ab initio thermodynamics supports the stability of these structures under a wide range of experimental conditions. The overlayers are found to have Ti2O3 stoichiometry with a crystal structure different from the known corundumlike Ti2O3 (here denoted a αTi2O3) phase. DFT calculations predict this new “cspTi2O3” phase to be energetically close to αTi2O3 and to have also a similar band gap. These results suggest a possible role of the cspTi2O3 phase in the properties of black TiO2, a promising photocatalytic material made of nanoparticles with a crystalline TiO2 core and a highly reduced TiOx shell that is capable of absorbing the whole spectrum of visible light.

  • Received 2 June 2017
  • Revised 4 September 2017

DOI:https://doi.org/10.1103/PhysRevMaterials.2.015801

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Physics Subject Headings (PhySH)

Condensed Matter & Materials Physics