Multilayer water adsorption on rutile TiO2(110): A first-principles study

Abstract

The adsorption of water on the TiO2(110) surface has become the model process in efforts to understand metal oxide–aqueous solution interfaces. Considerable progress has been made in understanding low-coverage situations where first-principle calculations have been employed to good effect. However, current theory is less well developed for coverage above one monolayer. Here we present results of calculations on the adsorption process in forming the second water layer, that is, the adsorption of water on the fully hydrated surface. We show that there are many competitive adsorption sites owing to the numerous hydrogen-bonding possibilities. The presence of the second layer water molecules facilitates proton transfer among the adsorbates within chainlike configurations, and we present some illustration of these processes. We show how the adsorption energetics computed here along with recent calculations on defective surface and low-coverage adsorption may be used to provide a satisfactory interpretation of the temperature programmed desorption data for this system. Finally, we compute the vibrational spectrum for H and compare with the high-resolution electron-energy-loss spectroscopy measurements.

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

“…Conclusively, it has been made clear that the symmetry-breaking induced by the interactions between adsorbates benefits the system energetically. Although the symmetry effects discussed above are quite crucial, they have not been described in detail in previous studies 34,[42][43][44][45][46][47][48]66,100 . 78 are shown for relaxed geometries in two-molecule adsorption.…”

“…[36][37][38][39][40][41][42][43][44][45][46] It should be noted, however, that many of these simulations are based on structural models characterized by either point group or translational symmetry constraints. Semiempirical tight-binding studies based on cluster models by Goniakowski et al and Bredow et al show favorable dissociative adsorption at all coverages, [36][37][38] as do some early first-principles Hartree-Fock (HF) and density functional theory (DFT) studies.…”

“…This terminology has been used in the present study in order to highlight the importance of breaking translational symmetry in intermolecular interactions as well as to be consistent with the language adopted in previous theoretical water adsorption studies. 34,43,[46][47][48]50,66 Molecular, dissociative and mixed adsorption modes are considered at each coverage and/or arrangement of adsorbates on the surface. This paper is organised as follows.…”

Diffusion and reaction pathways of water near fully hydrated TiO2 surfaces from ab initio molecular dynamics

“…29 However, biological environments are usually fully hydrated. Experiments 32 and computations 49,50 have shown that the structure of the hydration layer changes as the water amount is increased beyond monolayer coverage, presumably because of hydrogen bonding between the first and second water layers. Consequently, the adsorption behavior for larger molecules on TiO 2 is expected to be different for fully and partially hydrated surfaces.…”

Reactions and clustering of water with silica surface

“…Much work has been done to investigate the adsorption of water on metal [1][2][3][4] and oxide [5][6][7][8][9][10] surfaces. It is well established that the adsorption of water can be either molecular or partially dissociative, depending on the water coverage.…”