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Band Positions of Anatase (001) and (101) Surfaces in Contact with Water from Density Functional Theory

preprint
submitted on 07.05.2020 and posted on 08.05.2020 by Julian Geiger, Michiel Sprik, Matthias May
Titanium dioxide in the anatase configuration plays an increasingly important role for photo(electro)catalytic applications due to its superior electronic properties when compared to rutile. In aqueous environments, the surface chemistry and energetic band positions upon contact with water determine charge-transfer processes over solid--solid or solid--electrolyte interfaces. Here, we study the interaction of anatase (001) and (101) surfaces with water and the resulting energetic alignment by means of hybrid density functional theory. While the alignment of band positions favours charge-transfer processes between the two facets for the pristine surfaces, we find the magnitude of this underlying driving force to crucially depend on water coverage and degree of dissociation. It can be largely alleviated for intermediate water coverages. Surface states and their passivation by dissociatively adsorbed water play an important role here. Our results suggest that anatase band positions can be controlled over a range of almost one eV via its surface chemistry.

Funding

EPSRC (EP/P022596/1)

International Exchanges grant IE161814 of the Royal Society

German National Academy of Sciences Leopoldina, grant LPDS 2015-09

German Research Foundation, project 434023472

Volkswagen Foundation

History

Email Address of Submitting Author

matthias.may@uni-ulm.de

Institution

Ulm University

Country

Germany

ORCID For Submitting Author

0000-0002-1252-806X

Declaration of Conflict of Interest

No conflict of interest.

Version Notes

The following article has been accepted by the Journal of Chemical Physics. After it is published, it will be found at https://doi.org/10.1063/5.0004779.

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