Abstract
Formation of oxygen vacancies (VO) is an important step of many catalytic reactions following the Mars van Krevelen mechanism. High rate of oxidation is associated with low energy of VO formation while high selectivity requires an optimal energy of VO formation. In the present computational study, enthalpy of VO formation (ΔHOVF) is studied in a decahedral anatase nanoparticle (TiO2)121(H2O)6 using PM6 method. ΔHOVF shows large variations for oxygen atoms in different locations on facets, edges and vertices. VO are much more stable in the (101) facet compared to the (001) facet, while internal VO are more stable for (101) but equally stable for (001) facet compared to surface vacancies on average. Comparison with literature DFT methods results reveals good consistency and high computational efficiency of the PM6 method for vacancies formation energy. Pm6 also correctly predicts admixture states of the Ti3+ within the band gap, but absolute values of electronic band gap and position of admixture states is overestimated and needs scaling factors.
Original language | English |
---|---|
Article number | e25806 |
Journal | International Journal of Quantum Chemistry |
Volume | 119 |
Issue number | 5 |
DOIs | |
State | Published - 5 Mar 2019 |
Externally published | Yes |
Keywords
- heterogeneous catalysis
- molecular modeling
- photocatalysis
- quantum dots
- semiempirical calculations