Eur. Phys. J. D 44, 515-524 (2007)
https://doi.org/10.1140/epjd/e2007-00186-5

Structural properties of amorphous TiO₂ nanoparticles

¹ Dept. of Physics, Institute of Technology, National Univ. of HochiMinh City, 268 Ly Thuong Kiet Str., Distr. 10, HochiMinh City, Vietnam
² Dept. of Science and Technology, National Univ. of HochiMinh City, HochiMinh City, Vietnam
³ Dept. of Mater. Sci., College of Natural Sci., Natl. Univ. of HochiMinh City, HochiMinh City, Vietnam

Corresponding author: ^a vvhoang2002@yahoo.com

Received: 16 November 2006
Revised: 30 March 2007
Published online: 8 June 2007

Abstract

Structural properties of amorphous TiO₂ spherical nanoparticles have been studied in models with different sizes of 2 nm, 3 nm, 4 nm and 5 nm under non-periodic boundary conditions. We use the pairwise interatomic potentials proposed by Matsui and Akaogi. Models have been obtained by cooling from the melt via molecular dynamics (MD) simulation. Structural properties of an amorphous nanoparticle obtained at 350 K have been analyzed in detail through the partial radial distribution functions (PRDFs), coordination number distributions, bond-angle distributions and interatomic distances. Moreover, we show the radial density profile in a nanoparticle. Calculations show that size effects on structure of a model are significant and that if the size is larger than 3 nm, amorphous TiO₂ nanoparticles have a distorted octahedral network structure with the mean coordination number Z_Ti-O ≈6.0 and Z_O-Ti ≈3.0 like those observed in the bulk. Surface structure and surface energy of nanoparticles have been obtained and presented.