Single-site and monolayer surface hydration energy of anatase and rutile nanoparticles using density functional theory

Daniel R. Hummer, James D. Kubicki, Paul R.C. Kent, Peter J. Heaney

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Models of 1, 2, and 3 nm diameter anatase and rutile particles, with either a surface monolayer of water or a single water molecule at different surface sites, were subjected to energy minimizations using density functional theory (DFT). The optimized structures show that H2O molecules bind covalently to both anatase and rutile particles via undercoordinated Ti atoms at the surface of the particle, with a significant degree of hydrogen bonding to other surface waters and bridging oxygens. Ti-OH2 bonds are more highly ordered on anatase surfaces but are stronger on rutile surfaces. Energies of the fully optimized structures with and without water show that hydration of rutile surfaces is more strongly exothermic than is the hydration of anatase surfaces, and this effect becomes more pronounced as particle size decreases. Individual surface sites exhibit a wide range of hydration energies, explaining the strong experimental dependence of hydration energy on water coverage. The less exothermic surface hydration energy of anatase offsets its lower vacuum surface energy and makes rutile nanoparticles thermodynamically competitive with anatase in low-temperature aqueous solutions.

Original languageEnglish (US)
Pages (from-to)26084-26090
Number of pages7
JournalJournal of Physical Chemistry C
Volume117
Issue number49
DOIs
StatePublished - Dec 12 2013

Fingerprint

anatase
Hydration
rutile
Titanium dioxide
Density functional theory
hydration
Monolayers
density functional theory
Nanoparticles
nanoparticles
energy
Water
water
low vacuum
titanium dioxide
Molecules
surface water
Surface waters
Interfacial energy
surface energy

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Cite this

@article{c1166d220b1d49b1802a239ea0543371,
title = "Single-site and monolayer surface hydration energy of anatase and rutile nanoparticles using density functional theory",
abstract = "Models of 1, 2, and 3 nm diameter anatase and rutile particles, with either a surface monolayer of water or a single water molecule at different surface sites, were subjected to energy minimizations using density functional theory (DFT). The optimized structures show that H2O molecules bind covalently to both anatase and rutile particles via undercoordinated Ti atoms at the surface of the particle, with a significant degree of hydrogen bonding to other surface waters and bridging oxygens. Ti-OH2 bonds are more highly ordered on anatase surfaces but are stronger on rutile surfaces. Energies of the fully optimized structures with and without water show that hydration of rutile surfaces is more strongly exothermic than is the hydration of anatase surfaces, and this effect becomes more pronounced as particle size decreases. Individual surface sites exhibit a wide range of hydration energies, explaining the strong experimental dependence of hydration energy on water coverage. The less exothermic surface hydration energy of anatase offsets its lower vacuum surface energy and makes rutile nanoparticles thermodynamically competitive with anatase in low-temperature aqueous solutions.",
author = "Hummer, {Daniel R.} and Kubicki, {James D.} and Kent, {Paul R.C.} and Heaney, {Peter J.}",
year = "2013",
month = "12",
day = "12",
doi = "10.1021/jp408345v",
language = "English (US)",
volume = "117",
pages = "26084--26090",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "49",

}

Single-site and monolayer surface hydration energy of anatase and rutile nanoparticles using density functional theory. / Hummer, Daniel R.; Kubicki, James D.; Kent, Paul R.C.; Heaney, Peter J.

In: Journal of Physical Chemistry C, Vol. 117, No. 49, 12.12.2013, p. 26084-26090.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Single-site and monolayer surface hydration energy of anatase and rutile nanoparticles using density functional theory

AU - Hummer, Daniel R.

AU - Kubicki, James D.

AU - Kent, Paul R.C.

AU - Heaney, Peter J.

PY - 2013/12/12

Y1 - 2013/12/12

N2 - Models of 1, 2, and 3 nm diameter anatase and rutile particles, with either a surface monolayer of water or a single water molecule at different surface sites, were subjected to energy minimizations using density functional theory (DFT). The optimized structures show that H2O molecules bind covalently to both anatase and rutile particles via undercoordinated Ti atoms at the surface of the particle, with a significant degree of hydrogen bonding to other surface waters and bridging oxygens. Ti-OH2 bonds are more highly ordered on anatase surfaces but are stronger on rutile surfaces. Energies of the fully optimized structures with and without water show that hydration of rutile surfaces is more strongly exothermic than is the hydration of anatase surfaces, and this effect becomes more pronounced as particle size decreases. Individual surface sites exhibit a wide range of hydration energies, explaining the strong experimental dependence of hydration energy on water coverage. The less exothermic surface hydration energy of anatase offsets its lower vacuum surface energy and makes rutile nanoparticles thermodynamically competitive with anatase in low-temperature aqueous solutions.

AB - Models of 1, 2, and 3 nm diameter anatase and rutile particles, with either a surface monolayer of water or a single water molecule at different surface sites, were subjected to energy minimizations using density functional theory (DFT). The optimized structures show that H2O molecules bind covalently to both anatase and rutile particles via undercoordinated Ti atoms at the surface of the particle, with a significant degree of hydrogen bonding to other surface waters and bridging oxygens. Ti-OH2 bonds are more highly ordered on anatase surfaces but are stronger on rutile surfaces. Energies of the fully optimized structures with and without water show that hydration of rutile surfaces is more strongly exothermic than is the hydration of anatase surfaces, and this effect becomes more pronounced as particle size decreases. Individual surface sites exhibit a wide range of hydration energies, explaining the strong experimental dependence of hydration energy on water coverage. The less exothermic surface hydration energy of anatase offsets its lower vacuum surface energy and makes rutile nanoparticles thermodynamically competitive with anatase in low-temperature aqueous solutions.

UR - http://www.scopus.com/inward/record.url?scp=84890447603&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84890447603&partnerID=8YFLogxK

U2 - 10.1021/jp408345v

DO - 10.1021/jp408345v

M3 - Article

AN - SCOPUS:84890447603

VL - 117

SP - 26084

EP - 26090

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 49

ER -