What Controls Photocatalytic Water Oxidation on Rutile TiO2(110) under Ultra-High-Vacuum Conditions?
dc.contributor.author
dc.date.accessioned
2019-07-29T08:16:12Z
dc.date.available
2019-07-29T08:16:12Z
dc.date.issued
2017-08-03
dc.identifier.issn
0002-7863
dc.identifier.uri
dc.description.abstract
The photocatalytic O–H dissociation of water absorbed on a rutile TiO2(110) surface in ultrahigh vacuum (UHV) is studied with spin-polarized density functional theory and a hybrid exchange-correlation functional (HSE06), treating the excited-state species as excitons with triplet multiplicity. This system is a model for the photocatalytic oxidation of water by TiO2 in an aqueous medium, which is relevant for the oxygen evolution reaction and photodegradation of organic pollutants. We provide a comprehensive mechanistic picture where the most representative paths correspond to excitonic configurations with the hole located on three- and two-coordinate surface oxygen atoms (O3s and O2s). Our picture explains the formation of the species observed experimentally. At near band gap excitation, the O3s path leads to the generation of hydroxyl anions which diffuse on the surface, without net oxidation. In contrast, free hydroxyl radicals are formed at supra band gap excitation (e.g., 266 nm) from an interfacial exciton that undergoes O–H dissociation. The oxidation efficiency is low because the path associated with the O2s exciton, which is the most favored one thermodynamically, is unreactive because of a high propensity for charge recombination. Our results are also relevant to understand the reactivity in the liquid phase. We assign the photoluminescence measured for atomically flat TiO2(110) surfaces in an aqueous medium to the O3s exciton, in line with the proposal based on experiments, and we have identified a species derived from the O2s exciton with an activated O2s–Ti bond that may be relevant in photocatalytic applications in an aqueous medium
dc.description.sponsorship
We acknowledge financial support from the Spanish Ministerio
de Economıá y Competitividad (Grants UNGI10-4E-801,
RYC-2011-09582, and CTQ-2015-69363-P) and Generalitat
de Catalunya (Grant 2014SGR-1202, XRQTC) and computational
time from the BSC Red Espanola de Supercomputación
and Consorci de Serveis Universitaris de Catalunya
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier
dc.relation
info:eu-repo/grantAgreement/MINECO//CTQ2015-69363-P/ES/OMPUTACION DEL ESTADO EXCITADO: DE ESPECTROS MOLECULARES A SISTEMAS MULTICROMOFORICOS/
dc.relation.isformatof
Reproducció digital del document publicat a: https://doi.org/10.1021/jacs.7b05121
dc.relation.ispartof
© Journal of the American Chemical Society, 2017, vol. 139, núm. 34, p. 11845-11856
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Articles publicats (D-Q)
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Tots els drets reservats
dc.title
What Controls Photocatalytic Water Oxidation on Rutile TiO2(110)
under Ultra-High-Vacuum Conditions?
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/openAccess
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.identifier.idgrec
027532
dc.contributor.funder
dc.type.peerreviewed
peer-reviewed
dc.relation.ProjectAcronym
dc.identifier.eissn
1520-5126