Abstract
Scanning tunneling microscopy (STM) has been used to investigate the adsorption of benzoic acid on the rutile TiO2(110)(1 x 1) and the reconstructed TiO2(110)(1 x 2) surfaces. Benzoic acid binds to both surfaces dissociatively via a bridging geometry to two Ti-5c sites. At a slightly elevated sample temperature during deposition onto the (110) (1 x 1) surface, a well-ordered (2 x 1) overlayer was formed at saturated benzoate coverage. On the reconstructed (110) (1 x 2) surface, benzoate was observed to adsorb between the (1 x 2) strands leading to a (2 x 2) superstructure at higher coverage. Elongation along the [1 (1) over bar0] direction in the STM images indicates a rotation of the benzene ring of 90 degrees relative to the carboxylate group, which is reasonably explained by hydrogen bond interactions between terminating O-atoms on the surface and H-atoms of the ring.