TiO2 nanoparticles (NPs) are nowadays considered fundamental building blocks for many technological applications. Morphology is found to play a key role with spherical NPs presenting higher binding properties and chemical activity. From the experimental point of view, the characterization of these nano-objects is extremely complex, opening a large room for computational investigations. In this work, TiO2 spherical NPs of different sizes (from 300 to 4000 atoms) have been studied with a two-scale computational approach. Global optimization to obtain stable and equilibrated nanospheres was performed with a self-consistent charge density functional tight-binding (SCC-DFTB) simulated annealing process, causing a considerable atomic rearrangement within the nanospheres. Those SCC-DFTB relaxed structures have been then optimized at the DFT(B3LYP) level of theory. We present a systematic and comparative SCC-DFTB vs DFT(B3LYP) study of the structural properties, with particular emphasis on the surface-to-bulk sites ratio, coordination distribution of surface sites, and surface energy. From the electronic point of view, we compare HOMO-LUMO and Kohn-Sham gaps, total and projected density of states. Overall, the comparisons between DFTB and hybrid density functional theory show that DFTB provides a rather accurate geometrical and electronic description of these nanospheres of realistic size (up to a diameter of 4.4 nm) at an extremely reduced computational cost. This opens for new challenges in simulations of very large systems and more extended molecular dynamics.
Selli, D., Fazio, G., & Di Valentin, C. (2017). Modelling realistic TiO2 nanospheres: A benchmark study of SCC-DFTB against hybrid DFT. THE JOURNAL OF CHEMICAL PHYSICS, 147(16) [10.1063/1.4994165].
|Citazione:||Selli, D., Fazio, G., & Di Valentin, C. (2017). Modelling realistic TiO2 nanospheres: A benchmark study of SCC-DFTB against hybrid DFT. THE JOURNAL OF CHEMICAL PHYSICS, 147(16) [10.1063/1.4994165].|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Presenza di un coautore afferente ad Istituzioni straniere:||No|
|Titolo:||Modelling realistic TiO2 nanospheres: A benchmark study of SCC-DFTB against hybrid DFT|
|Autori:||Selli, D; Fazio, G; Di Valentin, C|
SELLI, DANIELE (Primo)
FAZIO, GIANLUCA (Secondo)
DI VALENTIN, CRISTIANA (Ultimo) (Corresponding)
|Data di pubblicazione:||2017|
|Rivista:||THE JOURNAL OF CHEMICAL PHYSICS|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1063/1.4994165|
|Appare nelle tipologie:||01 - Articolo su rivista|