Oxygen vacancy related distortions in rutile TiO_2 nanoparticles: a combined experimental and theoretical study

©2016 American Physical Society. This paper has been supported by the Norway, Iceland, Liechtenstein Science and Sustainability (NILS)/EEA Grants “Sustainable oxide materials and nanostructures for energy related applications (SUSOX)” (Project No. 008-ABELCM- 2013), Norwegian Metacenter for Computational Science (Notur) Project No. nn4608k, Ministry of Economy, Industry and Competitiveness (MINECO)/European Regional Development Fund (FEDER) Project No. MAT2015-65274-R, and Consolider Ingenio Project No. CSD 2009-00013. The authors thank Dr. A. Pishtshev for practical help, Dr. J. RamírezCastellanos for kindly providing the TiO_2 nanoparticles, and the BACH beamline staff for useful advice on XPS and XAS measurements at the Elettra Synchrotron in Trieste. The work by S.Z.K. has been supported by New Indigo Project No. 237643/E20.
The effects of doubly ionized oxygen vacancies [(V_O)ˆ(2+)]on the electronic structure and charge distribution in rutile TiO_2 are studied by combining first-principles calculations based on density functional theory and experimental results from x-ray photoelectron and x-ray absorption measurements carried out in synchrotron facilities on rutile TiO_2 nanoparticles. The generalized gradient approximation of the Perdew-Burke-Ernzerhof functional has demonstrated its suitability for the analysis of the [(V_O)ˆ(2+)]defects in rutile TiO_2. It has been found that the presence of empty electronic states at the conduction band shifted ̴1 eV from t_(2g) and e_(g) states can be associated with local distortions induced by [(V_O)ˆ(2+)]defects, in good agreement with Gauss-Lorentzian band deconvolution of experimental O K-edge spectra. The asymmetry of t(2g) and e(g) bands at the O-K edge has been associated with [(V_O)ˆ(2+)], which can enrich the understanding of studies where the presence of these defects plays a key role, as in the case of doped TiO_2.
Unión Europea. FP7
Ministerio de Economía y Competitividad (MINECO)
European Regional Development Fund (FEDER)
Norway, Iceland, Liechtenstein Science and Sustainability (NILS)/EEA Grants "Sustainable oxide materials and nanostructures for energy related applications (SUSOX)"
Norwegian Metacenter for Computational Science (Notur)
Consolider Ingenio Project
New Indigo Project
Depto. de Física de Materiales
Fac. de Ciencias Físicas
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