Action of chloride ions as a habit modifier in the hydrothermal crystal growth of rutile TiO2 nanorod from SnO2 seed crystal

Abstract

The mechanism of hydrothermal heteroepitaxial growth of rutile TiO2 nanorods from SnO2 seed nanocrystals under acidic conditions was studied. On the basis of the experimental and density functional theory (DFT) simulation results, we have presented a reaction mechanism that chloride ions are preferentially adsorbed on the oxygen-defect sites on the (110) plane of TiO2 to suppress the growth, and consequently, TiO2 grows in the [001] direction to yield the nanorod with the (110)-faceted side walls. Importantly, the DFT simulations indicated that easy defect formation on the (110) facet is a key to the preferential adsorption of chloride ions.