TiO2 anatase's bulk and (001) surface, structural and electronic properties: A DFT study on the importance of Hubbard and van der Waals contributions

• Published in: Surface science Vol. 653; pp. 187 - 196
• Main Authors: Araujo-Lopez, Eduard, Varilla, Luis Alcala, Seriani, Nicola, Montoya, Javier A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2016
• Subjects: Anatase; CO2 adsorption; DFT+U; Dispersion forces; surface; TiO2; vdW; DFT+U; Anatase; surface; vdW; Dispersion forces; CO2 adsorption; TiO2
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2016.07.003

Theoretical ab initio studies done so far on the structural properties of the titanium dioxide anatase (001) surface, have not reported simultaneously the complete set of cell and interatomic parameters for this system or its bulk. Here we present a complete report of these quantities within a spin polarized Density Functional Theory calculation, including also the Hubbard term and the van der Waals dispersion contribution. We show that within this approach it is possible to find a description of TiO2 anatase using DFT, that correlates better with experimental results than most theoretical studies reported previously. This good level of agreement has an advantage with respect to other very accurate studies which have performed computationally expensive calculations involving hybrid functionals, in that our method tends to be faster while also including the van der Waals dispersion contributions in addition to the treatment of correlations. The observed high-quality description of a system like TiO2 within this approach is important and encouraging; specially because it treats properly a d-shell element that is possibly going to have, for many applications of interest, long-range interaction with molecules, e.g. in studies of photocatalysis, where one needs all the relevant physics of the system to be included. We support this claim with an example of the effects that long-range interactions have on a CO2 molecule at the (001) surface. [Display omitted] •DFT+U+VdW reproduce very well the structural properties of TiO2 anatase's bulk.•The bulk and (001) surface of anatase are compared with several previous studies.•Relevant effects coming from the VdW corrections are observed on the clean surface.•The DFT+U+VdW approach is computationally efficient and offers good accuracy.