skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4

Abstract

In the low energy structures of the (TiO2)n(H2O)m (n ≤ 4, m ≤ 2n) and (TiO2)8(H2O)m (m = 3, 7, 8) clusters were predicted using a global geometry optimization approach, with a number of new lowest energy isomers being found. Water can molecularly or dissociatively adsorb on pure and hydrated TiO2 clusters. Dissociative adsorption is the dominant reaction for the first two H2O adsorption reactions for n = 1, 2, and 4, for the first three H2O adsorption reactions for n = 3, and for the first four H2O adsorption reactions for n = 8. As more H2O’s are added to the hydrated (TiO2)n cluster, dissociative adsorption becomes less exothermic as all the Ti centers become 4-coordinate. Furthermore two types of bonds can be formed between the molecularly adsorbed water and TiO2 clusters: a Lewis acid–base Ti–O(H2) bond or an O···H hydrogen bond. The coupled cluster CCSD(T) results show that at 0 K the H2O adsorption energy at a 4-coordinate Ti center is ~15 kcal/mol for the Lewis acid–base molecular adsorption and ~7 kcal/mol for the H-bond molecular adsorption, in comparison to that of 8–10 kcal/mol for the dissociative adsorption. The cluster size and geometry independent dehydration reaction energy, ED,more » for the general reaction 2(-TiOH) → -TiOTi– + H2O at 4-coordinate Ti centers was estimated from the aggregation reaction of nTi(OH)4 to form the monocyclic ring cluster (TiO3H2)n + nH2O. ED is estimated to be -8 kcal/mol, showing that intramolecular and intermolecular dehydration reactions are intrinsically thermodynamically allowed for the hydrated (TiO2)n clusters with all of the Ti centers 4-coordinate, which can be hindered by cluster geometry changes caused by such processes. Finally by bending force constants for the TiOTi and OTiO bonds are determined to be 7.4 and 56.0 kcal/(mol·rad2). Infrared vibrational spectra were calculated using density functional theory, and the new bands appearing upon water adsorption were assigned.« less

Authors:
 [1];  [2];  [3]
  1. Univ. of Alabama, Tuscaloosa, AL (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Univ. of Alabama, Tuscaloosa, AL (United States)
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Energy Frontier Research Centers (EFRC) (United States). Center for Understanding and Control of Acid Gas-induced Evolution of Materials for Energy (UNCAGE-ME)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1265877
Grant/Contract Number:  
AC05-00OR22725; SC0012577
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
Additional Journal Information:
Journal Volume: 119; Journal Issue: 46; Journal ID: ISSN 1089-5639
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS

Citation Formats

Chen, Mingyang, Straatsma, Tjerk P., and Dixon, David A. Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4. United States: N. p., 2015. Web. doi:10.1021/acs.jpca.5b07697.
Chen, Mingyang, Straatsma, Tjerk P., & Dixon, David A. Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4. United States. https://doi.org/10.1021/acs.jpca.5b07697
Chen, Mingyang, Straatsma, Tjerk P., and Dixon, David A. 2015. "Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4". United States. https://doi.org/10.1021/acs.jpca.5b07697. https://www.osti.gov/servlets/purl/1265877.
@article{osti_1265877,
title = {Molecular and Dissociative Adsorption of Water on (TiO 2 ) n Clusters, n = 1–4},
author = {Chen, Mingyang and Straatsma, Tjerk P. and Dixon, David A.},
abstractNote = {In the low energy structures of the (TiO2)n(H2O)m (n ≤ 4, m ≤ 2n) and (TiO2)8(H2O)m (m = 3, 7, 8) clusters were predicted using a global geometry optimization approach, with a number of new lowest energy isomers being found. Water can molecularly or dissociatively adsorb on pure and hydrated TiO2 clusters. Dissociative adsorption is the dominant reaction for the first two H2O adsorption reactions for n = 1, 2, and 4, for the first three H2O adsorption reactions for n = 3, and for the first four H2O adsorption reactions for n = 8. As more H2O’s are added to the hydrated (TiO2)n cluster, dissociative adsorption becomes less exothermic as all the Ti centers become 4-coordinate. Furthermore two types of bonds can be formed between the molecularly adsorbed water and TiO2 clusters: a Lewis acid–base Ti–O(H2) bond or an O···H hydrogen bond. The coupled cluster CCSD(T) results show that at 0 K the H2O adsorption energy at a 4-coordinate Ti center is ~15 kcal/mol for the Lewis acid–base molecular adsorption and ~7 kcal/mol for the H-bond molecular adsorption, in comparison to that of 8–10 kcal/mol for the dissociative adsorption. The cluster size and geometry independent dehydration reaction energy, ED, for the general reaction 2(-TiOH) → -TiOTi– + H2O at 4-coordinate Ti centers was estimated from the aggregation reaction of nTi(OH)4 to form the monocyclic ring cluster (TiO3H2)n + nH2O. ED is estimated to be -8 kcal/mol, showing that intramolecular and intermolecular dehydration reactions are intrinsically thermodynamically allowed for the hydrated (TiO2)n clusters with all of the Ti centers 4-coordinate, which can be hindered by cluster geometry changes caused by such processes. Finally by bending force constants for the TiOTi and OTiO bonds are determined to be 7.4 and 56.0 kcal/(mol·rad2). Infrared vibrational spectra were calculated using density functional theory, and the new bands appearing upon water adsorption were assigned.},
doi = {10.1021/acs.jpca.5b07697},
url = {https://www.osti.gov/biblio/1265877}, journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
issn = {1089-5639},
number = 46,
volume = 119,
place = {United States},
year = {Tue Oct 20 00:00:00 EDT 2015},
month = {Tue Oct 20 00:00:00 EDT 2015}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 38 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Electrochemical Photolysis of Water at a Semiconductor Electrode
journal, July 1972


Chemisorbed phases of H2O on TiO2 and SrTiO3
journal, December 1977


Photoassisted water-gas shift reaction over platinized titanium dioxide catalysts
journal, November 1980


Photolysis of Water and Photoreduction of Nitrogen on Titanium Dioxide
journal, October 1977


Size-Selected TiO 2 Nanocluster Catalysts for Efficient Photoelectrochemical Water Splitting
journal, November 2014


Structure and Stability of Small TiO 2 Nanoparticles
journal, August 2005


Theoretical Study of the Electronic Structure and Stability of Titanium Dioxide Clusters (TiO 2 ) n with n = 1−9
journal, May 2006


Molecular Structures and Energetics of the (TiO 2 ) n ( n = 1−4) Clusters and Their Anions
journal, July 2008


Tree Growth—Hybrid Genetic Algorithm for Predicting the Structure of Small (TiO 2 ) n , n = 2–13, Nanoclusters
journal, June 2013


Coupled cluster calculations on TiO 2 nanoclusters
journal, August 2013


Computational Study of the Hydrolysis Reactions of the Ground and First Excited Triplet States of Small TiO 2 Nanoclusters
journal, April 2011


Computational Study of H 2 and O 2 Production from Water Splitting by Small (MO 2 ) n Clusters (M = Ti, Zr, Hf)
journal, April 2013


An open-shell spin-restricted coupled cluster method: application to ionization potentials in nitrogen
journal, June 1988


Coupled cluster theory for high spin, open shell reference wave functions
journal, October 1993


Perturbative corrections to account for triple excitations in closed and open shell coupled cluster theories
journal, September 1994


Coupled-cluster theory in quantum chemistry
journal, February 2007


Structure and Vibrational Spectra of Ti(IV) Hydroxides and Their Clusters with Expanded Titanium Coordination. DFT Study
journal, August 2007


Modeling Excited States in TiO 2 Nanoparticles: On the Accuracy of a TD-DFT Based Description
journal, February 2014


Inhomogeneous Electron Gas
journal, November 1964


Self-Consistent Equations Including Exchange and Correlation Effects
journal, November 1965


Density‐functional thermochemistry. III. The role of exact exchange
journal, April 1993


Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density
journal, January 1988


Optimization of Gaussian-type basis sets for local spin density functional calculations. Part I. Boron through neon, optimization technique and validation
journal, February 1992


Electron affinities of the first‐row atoms revisited. Systematic basis sets and wave functions
journal, May 1992


Accurate Thermochemistry for Transition Metal Oxide Clusters
journal, July 2009


Improved relativistic energy-consistent pseudopotentials for 3d-transition metals
journal, September 2005


Works referencing / citing this record:

Properties of hydrated TiO 2 and SiO 2 nanoclusters: dependence on size, temperature and water vapour pressure
journal, January 2018


High-resolution photoelectron spectroscopy of TiO 3 H 2 : Probing the TiO 2 + H 2 O dissociative adduct
journal, June 2018