Water adsorption on rutile TiO2(110) for applications in solar hydrogen production: A systematic hybrid-exchange density functional study

Abstract

Periodic hybrid-exchange density functional theory calculations are used to predict the structure of water on the rutile TiO 2 (110) surface ( 1 ML), which is an important first step towards understanding the photocatalytic processes that occur in solar water splitting. A detailed model describing the water-water and water-surface interactions is developed by exploring thoroughly the adsorption energetics. The possible adsorption mode-molecular, dissociative, or mixed-and the binding energy are studied as a function of coverage and arrangement, thus separation, of adsorbed species. These dependencies (coverage and arrangement) have a significant influence on the nature of the interactions involved in the H 2 O-TiO 2 system. The importance of both direct intermolecular and surface-mediated interactions between surface species is emphasized. Finally, to gain insight into the photooxidation of adsorbed species at the surface, the electronic structure of the predicted adsorbate-substrate geometries is analyzed in terms of total and projected density of states.

Water adsorption on TiO2 surfaces probed by soft X-ray spectroscopies: bulk materials vs. isolated nanoparticles

“…A difference between dry and solvated NPs cases is evidenced: the band bending of the valence edge accompanying the hydrated state and the shift towards higher BE is in full agreement with the observation made by Kurtz et al 46 on bulk hydrated TiO 2 surfaces. The same behaviour was highlighted with DFT calculations 47 and was attributed to a solvation of TiO 2 surface states due to water adsorption.…”

Energy level alignment at semiconductor–water interfaces from atomistic and continuum solvation models

“…87 Furthermore, as mentioned previously, the structure of the rst monolayer of water molecules at the interface may differ from the one assumed here. 54,55 Direct comparison with experiment requires careful consideration of these issues and we emphasise that our focus is not on comparison with experiment, but on the comparison between atomistic and continuum solvation models of the electrolyte.…”

“…The initial congurations of the water molecules, which were assumed to be those found by Patel et al, were relaxed using the BFGS algorithm. 54 In reality, the water molecules of the rst monolayer at the rutile(110) surface are very likely to be at least partially dissociated. 55 However, as the focus of this work is on the comparison between atomistic and continuum solvation models, we only require consistency between these two methods.…”

Modeling Kinetics of Water Adsorption on the Rutile TiO2 (110) Surface: Influence of Exchange‐Correlation Functional

“…Dissociation on stoichiometric TiO 2 (110) has been a much more controversial topic . However, the most recent experimental and theoretical efforts are consistent in that the first water layer on a defect‐free surface is partially dissociated . On the basis of XPS in conjunction with density functional theory (DFT) calculations and Monte Carlo simulations to study the wetting of TiO 2 (110), it was possible to derive a mechanism for the OH and H 2 O speciation, which is found to vary with coverage .…”