Relative Stability of F-Covered TiO2 Anatase (101) and (001) Surfaces from Periodic DFT Calculations and ab Initio Atomistic Thermodynamics

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• 作者：Oriol Lamiel-Garcia ; Sergio Tosoni ; Francesc Illas
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：June 26, 2014
• 年：2014
• 卷：118
• 期：25
• 页码：13667-13673
• 全文大小：363K
• ISSN：1932-7455

文摘

A density functional theory based computational study is presented of fluorine adsorption on anatase TiO₂(101) and TiO₂(001) surfaces. A variety of surface coverage situations ranging from 10 to 100% have been considered, and the effect on the electronic structure of the material has been analyzed. The adsorption of F atoms on these surfaces directly affects the band structure with new features in the band gap due to the presence of partially oxidized anions. The effect of F coverage on the relative stability of both surfaces has been studied by applying the ab initio thermodynamic formalism. Interestingly, the effect of fluorine on the surface free energy at 298.15 K and 1 bar of F₂ pressure is to stabilize the (001) surface and destabilize the (101), which nicely explains the experimental observation that the presence of F allows growing TiO₂ anatase nanoparticles with a higher percentage of the more reactive 001 surface with enhanced photocatalytic activity.