Molecular dynamics study of water in contact with the TiO₂ rutile-110, 100, 101, 001 and anatase-101, 001 surface

Abstract

We have carried out classical molecular dynamics of various surfaces of TiO₂ with its interface with water. We report the geometrical features of the first and second monolayers of water using a Matsui Akaogi (MA) force field for the TiO₂ surface and a flexible single point charge model for the water molecules. We show that the MA force field can be applied to surfaces other than rutile (110). It was found that water OH bond lengths, H–O–H bond angles and dipole moments do not vary due to the nature of the surface. However, their orientation within the first and second monolayers suggest that planar rutile (001) and anatase (001) surfaces may play an important role in not hindering removal of the products formed on these surfaces. Also, we discuss the effect of surface termination in order to explain the layering of water molecules throughout the simulation box.

Keywords:

• molecular dynamics
• TiO₂ surface
• oxide–water interface
• rutile
• anatase

Acknowledgements

The authors acknowledge useful conversations with Dr. Damian Mooney. This material is based upon works supported by the Science Foundation Ireland (SFI) under grant No. 07/SRC/B1160, in addition to the Irish Research Council for Science, Engineering and Technology. We also thank SFI and the Irish Centre for High End Computing for the provision of high-performance computing facilities.