Electronic charge of SnO2 grains: a quantum mechanical study of structure effects and adsorption capabilities

This study has been conducted to get insight into the properties of SnO2 nanocrystalline materials. Therefore, the Hartree-Fock formulation at semi-empirical level, using the Extended Debye-Huckel Approximation, has been applied to the characterization of the electronic charge of realistic grain structures. The grains have the rutile lattice of SnO2. Their shape is columnar or spherical and their maximum size reaches 600 atoms (i.e. their linear dimension is in the range 2 nm). The parameters investigated are the binding energies, the charge on atoms, the spectrum of allowed energies and the properties of adsorption of O-2 and CO molecules. The effects of grain size and shape are discussed.