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Title: Comparing Quasiparticle H 2O Level Alignment on Anatase and Rutile TiO 2

Knowledge of the alignment of molecular frontier levels in the ground state can be used to predict the photocatalytic activity of an interface. The position of the adsorbate’s highest occupied molecular orbital (HOMO) levels relative to the substrate’s valence band maximum (VBM) in the interface describes the favorability of photogenerated hole transfer from the VBM to the adsorbed molecule. This is a key quantity for assessing and comparing H 2O photooxidation activities on two prototypical photocatalytic TiO 2 surfaces: anatase (A)-TiO 2(101) and rutile (R)-TiO 2(110). Using the projected density of states (DOS) from state-of-the-art quasiparticle (QP) G 0W 0 calculations, we assess the relative photocatalytic activity of intact and dissociated H 2O on coordinately unsaturated (Ticus) sites of idealized stoichiometric A-TiO 2(101)/R-TiO 2(110) and bridging O vacancies (O br vac) of defective A-TiO 2-x(101)/R-TiO 2-x(110) surfaces (x = 1/4, 1/8) for various coverages. Such a many-body treatment is necessary to correctly describe the anisotropic screening of electron-electron interactions at a photocatalytic interface and, hence, obtain accurate interfacial level alignments. The more favorable ground state HOMO level alignment for A-TiO 2(101) may explain why the anatase polymorph shows higher photocatalytic activities than the rutile polymorph. Our results indicate that (1)more » hole trapping is more favored on A-TiO 2(101) than RTiO 2(110) and (2) HO@Ti cus is more photocatalytically active than intact H 2O@Ti cus.« less
Authors:
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Publication Date:
OSTI Identifier:
1214069
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Catalysis, 5(7):4242–4254
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory