Binding of a Benzoate Dye-Molecule Analogue to Rutile Titanium Dioxide Surfaces

Structure of a Model Dye/Titania Interface: Geometry of Benzoate on Rutile-TiO2 (110)(1 × 1)

“…attachment to the surface is through both of the carboxylate oxygen atoms to two adjacent five-fold surface titanium atoms; scanned-energy mode PhD data are normally most sensitive to nearest neighbor atoms below the emitting atom 23,24 . Such a conclusion is in agreement with previous proposals/predictions of the local adsorption geometry of benzoate on TiO 2 (110)(1×1) 2,4,[25][26][27][28][29][30] .…”

“…Finally, we wish to compare the results of our current study with previous efforts to elucidate the adsorption geometry of benzoate on TiO 2 (110)(1×1) 2,4,[25][26][27]29,30 . Initally, we want to reemphasise that our PhD data are inconsistent with any overlayer structures involving benzoates where their phenyl groups exhibit two or more azimuthal orientations, a scenario suggested initially in Refs.…”

“…Concerning STM studies 2,[25][26][27]29 in which images have been interpreted to indicate the presence of twisted/tilted benzoate species (e.g. through dimer/trimer formation), substrate temperature/coverage may again underpin these observations.…”

“…Similarly, more recent work suggests that exposure of TiO 2 (110)(1×1) to benzoic acid, both in ultra high vacuum (UHV) 4,29 and in aqueous solution 2 , does not always simply result in a planar (and upright) benzoate species. These studies are, however, not in complete agreement, e.g.…”

“…4 are interpreted as indicating that benzoate-dimerization occurs as 0.5 ML coverage is approached, whereas STM images 29 suggest that dimers are not a feature of this coverage regime. On this basis, further effort is required to gain a more robust insight into the configuration of the adsorbed benzoate.…”