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Title: Interplay Between Hydrogen Bonding and Electron Solvation on Hydrated TiO2(110)

Abstract

We present density functional theory calculations of partially hydrated or “wet”-electron states on H2O and H-covered TiO2(110) surfaces. Based on the investigation of different coverages and structures, we determine different patterns of hydrogen bonding for the chemisorbed H2O and H on TiO2(110). We find that a network of dangling H atoms can stabilize photoexcited electrons, in so-called wet-electron states. The energies of the wet-electron states correlate closely with the number and configuration of the dangling H atoms. The effect of the adsorbate chemisorption on the surface charge distribution is also discussed. The calculated energies of the wet-electron states are in good agreement with those measured in two-photon photoemission experiments.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
917590
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter, 73:195309-1-195309-10; Journal Volume: 73
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; ATOMS; BONDING; CHARGE DISTRIBUTION; CHEMISORPTION; CONFIGURATION; ELECTRONS; FUNCTIONALS; HYDROGEN; PHOTOEMISSION; SOLVATION; TITANIUM OXIDES; Environmental Molecular Sciences Laboratory

Citation Formats

Zhao, Jin, Li, Bin, Jordan, Kenneth D., Yang, Jinlong, and Petek, Hrvoje. Interplay Between Hydrogen Bonding and Electron Solvation on Hydrated TiO2(110). United States: N. p., 2006. Web. doi:10.1103/PhysRevB.73.195309.
Zhao, Jin, Li, Bin, Jordan, Kenneth D., Yang, Jinlong, & Petek, Hrvoje. Interplay Between Hydrogen Bonding and Electron Solvation on Hydrated TiO2(110). United States. doi:10.1103/PhysRevB.73.195309.
Zhao, Jin, Li, Bin, Jordan, Kenneth D., Yang, Jinlong, and Petek, Hrvoje. Tue . "Interplay Between Hydrogen Bonding and Electron Solvation on Hydrated TiO2(110)". United States. doi:10.1103/PhysRevB.73.195309.
@article{osti_917590,
title = {Interplay Between Hydrogen Bonding and Electron Solvation on Hydrated TiO2(110)},
author = {Zhao, Jin and Li, Bin and Jordan, Kenneth D. and Yang, Jinlong and Petek, Hrvoje},
abstractNote = {We present density functional theory calculations of partially hydrated or “wet”-electron states on H2O and H-covered TiO2(110) surfaces. Based on the investigation of different coverages and structures, we determine different patterns of hydrogen bonding for the chemisorbed H2O and H on TiO2(110). We find that a network of dangling H atoms can stabilize photoexcited electrons, in so-called wet-electron states. The energies of the wet-electron states correlate closely with the number and configuration of the dangling H atoms. The effect of the adsorbate chemisorption on the surface charge distribution is also discussed. The calculated energies of the wet-electron states are in good agreement with those measured in two-photon photoemission experiments.},
doi = {10.1103/PhysRevB.73.195309},
journal = {Physical Review. B, Condensed Matter, 73:195309-1-195309-10},
number = ,
volume = 73,
place = {United States},
year = {Tue May 09 00:00:00 EDT 2006},
month = {Tue May 09 00:00:00 EDT 2006}
}
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  • Adsorption of Zn{sup 2+} at the rutile TiO{sub 2} (110)-aqueous interface was studied with Bragg-reflection X-ray standing waves (XSW), polarization-dependent surface extended X-ray absorption fine structure (EXAFS) spectroscopy, and density functional theory (DFT) calculations to understand the interrelated issues of adsorption site, its occupancy, ion-oxygen coordination and hydrolysis. At pH 8, Zn{sup 2+} was found to adsorb as an inner-sphere complex at two different sites, i.e., monodentate above the bridging O site and bidentate between two neighboring terminal O sites. EXAFS results directly revealed a four or fivefold first shell coordination environment for adsorbed Zn{sup 2+} instead of the sixfoldmore » coordination found for aqueous species at this pH. DFT calculations confirmed the energetic stability of a lower coordination environment for the adsorbed species and revealed that the change to this coordination environment is correlated with the hydrolysis of adsorbed Zn{sup 2+}. In addition, the derived adsorption locations and the occupancy factors of both sites from three methods agree well, with some quantitative discrepancies in the minor site location among the XSW, EXAFS, and DFT methods. Additional XSW measurements showed that the adsorption sites of Zn{sup 2+} were unchanged at pH 6. However, the Zn{sup 2+} partitioning between the two sites changed substantially, with an almost equal distribution between the two types of sites at pH 6 compared to predominantly monodentate occupation at pH 8.« less