Water Dissociation and Hydroxyl Ordering on Anatase TiO_{2}(001)-(1×4).

We studied the interaction of water with the anatase TiO_{2}(001) surface by means of scanning tunneling microscopy, x-ray photoelectron spectroscopy, and density functional theory calculations. Water adsorbs dissociatively on the ridges of a (1×4) reconstructed surface, resulting in a (3×4) periodic structure of hydroxyl pairs. We observed this process at 120 K, and the created hydroxyls desorb from the surface by recombination to water, which occurs below 300 K.

NH adsorption on anatase-TiO(101).

The adsorption of ammonia on anatase TiO is of fundamental importance for several catalytic applications of TiO and for probing acid-base interactions. Utilizing high-resolution scanning tunneling microscopy (STM), synchrotron X-ray photoelectron spectroscopy, temperature-programmed desorption (TPD), and density functional theory (DFT), we identify the adsorption mode and quantify the adsorption strength on the anatase TiO(101) surface. It was found that ammonia adsorbs non-dissociatively as NH on regular five-fold coordinated titanium surface sites (5f-Ti) with an estimated exothermic adsorption energy of 1.

Facile embedding of single vanadium atoms at the anatase TiO(101) surface.

To understand the structure-reactivity relationships for mixed-metal oxide catalysts, well-defined systems are required. Mixtures of vanadia and titania (TiO) are of particular interest for application in heterogeneous catalysis, with TiO often acting as the support. By utilizing high-resolution scanning tunneling microscopy, we studied the interaction of vanadium (V) with the anatase TiO(101) surface in the sub-monolayer regime.