First principles calculations on the stoichiometric and defective (101) anatase surface and upon hydrogen and H2Pc adsorption: The influence of electronic exchange and correlation and of basis set approximations
Entity
UAM. Departamento de Física de la Materia Condensada; UAM. Departamento de Física de MaterialesPublisher
Frontiers Research FoundationDate
2019-01-01Citation
10.3389/fchem.2019.00220
Frontiers in Chemistry 7.4 (2019): 220
ISSN
2296-2646DOI
10.3389/fchem.2019.00220Funded by
We acknowledge financial support from the Spanish MINECO through projects MDM-2014-0377, MAT2014-54484-P, and MAT2017-83273-R and a Juan de la Cierva contract (RM-C). Computer time was provided by the Spanish Supercomputing Network (RES, Spain) at the Magerit Supercomputer (Madrid, Spain) and via the membership of the UK’s HEC Materials Chemistry Consortium (GM and NH), which is funded by EPSRC (EP/L000202). This work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk)Project
Gobierno de España. MDM-2014-0377; Gobierno de España. MAT2014-54484-P; Gobierno de España. MAT2017-83273-REditor's Version
https://doi.org/10.3389/fchem.2019.00220Subjects
Anatase; Defects; Density functional theory; Hybrid functionals; Oxides; Phthalocyanine; FísicaRights
© 2019 Martínez-Casado, Todorović, Mallia, Harrison and PérezAbstract
Anatase TiO 2 provides photoactivity with high chemical stability at a reasonable cost. Different methods have been used to enhance its photocatalytic activity by creating band gap states through the introduction of oxygen vacancies, hydrogen impurities, or the adorption of phthalocyanines, which are usually employed as organic dyes in dye-sensitized solar cells. Predicting how these interactions affect the electronic structure of anatase requires an efficient and robust theory. In order to document the efficiency and accuracy of commonly used approaches we have considered two widely used implementations of density functional theory (DFT), namely the all-electron linear combination of atomic orbitals (AE-LCAO) and the pseudo-potential plane waves (PP-PW) approaches, to calculate the properties of the stoichiometric and defective anatase TiO 2 (101) surface. Hybrid functionals, and in particular HSE, lead to a computed band gap in agreement with that measured by using UV adsorption spectroscopy. When using PBE+U, the gap is underestimated by 20 % but the computed position of defect induced gap states relative to the conduction band minimum (CBM) are found to be in good agreement with those calculated using hybrid functionals. These results allow us to conclude that hybrid functionals based on the use of AE-LCAO provide an efficient and robust approach for predicting trends in the band gap and the position of gap states in large model systems. We extend this analysis to surface adsorption and use the AE-LCAO approach with the hybrid functional HSED3 to study the adsorption of the phthalocyanine H 2 Pc on anatase (101). Our results suggest that H 2 Pc prefers to be adsorbed on the surface Ti 5c rows of anatase (101), in agreement with that seen in recent STM experiments on rutile (110)
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Google Scholar:Martínez-Casado, Ruth
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Todorović, Milica
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Mallia, Giuseppe
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Harrison, Nicholas M.
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Pérez Pérez, Rubén
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