Paper SS-ThA8
Adsorption and One-Dimensional Chain Formation of Water on TiO₂(110)

Thursday, November 1, 2012, 4:20 pm, Room 22

The adsorption of water molecule on a reduced rutile TiO₂(110)-(1×1) surface has been investigated using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. STM results indicate that water monomer adsorbs on top of Ti(5f) atom on the Ti row. The DFT calculations show that the most stable configuration of adsorbed water on TiO₂(110) has the binding energy of 23.6 kcal/mol. In this configuration, the oxygen atom is positioned on top of a Ti(5f) atom with one of the O-H bonds pointing toward a bridging oxygen via H-bonding and the other pointing along the Ti row direction. The water monomer can be dissociated by the electron injection from the STM tip into an oxygen adatom on Ti row. As the coverage increases, water molecules start to form one-dimensional chains via H-bonding along the Ti row direction. Thermal annealing after the adsorption of water at low temperature on TiO₂(110) is also found to be effective in the formation of the one-dimensional water chain. The effects of other coadsorbates such as CO₂ and O₂ in the formation of water chain will also be discussed.