Spatial distribution of adsorbed water layers at the TiO2 rutile and anatase interfaces

The spatial distribution functions of adsorbed water layers at hydrated rutile-(110) and anatase-(101) surfaces have been studied at 300 K, using equilibrium classical molecular dynamics. It was found that there is evidence of some hydrogen-bonding with water molecules outside the adsorbed layer for anatase-(101), but less for rutile-(110) - on average, about 1.6 per water molecule in anatase-(101), in contrast to 0.9 for rutile-(110). This is due to adsorbed water molecules being confined more firmly in the area between bridging oxygen atoms at the rutile-110 surface, while the more open-like nature of anatase- 101 allows for greater contact with molecules outside the first layer. (C) 2012 Elsevier B.V. All rights reserved.