The origin of nanoscale phase stability reversals in titanium oxide polymorphs

Journal Article · Thu Jan 01 00:00:00 EST 2009 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/jp811332w· OSTI ID:958903

Hummer, Daniel R. ^[1]; Kubicki, James D. ^[1]; Heaney, Peter ^[1]; Kent, Paul R ^[2]; Post, Jeffrey E. ^[3]

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1. Pennsylvania State University
2. ORNL
3. Smithsonian

We have monitored the hydrothermal crystallization of titania nanoparticles by in situ X-ray diffraction, and our refined average structures cannot account for the stabilization of nano-anatase relative to nano-rutile. However, quantum mechanical calculations on model nanoparticles do generate lower surface energies for anatase than for rutile. These total surface energies derived not from 2-dimensional surface structure alone, as previously thought, but contained large contributions from defects associated with edges and corners of nanocrystals. This study quantifies for the first time the critical role of edge and vertex energies in determining the relative phase stabilities of polymorphic nanoparticles.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Sciences (NCCS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 958903
• Journal Information: Journal of Physical Chemistry. C, Vol. 113, Issue 11; ISSN 1932-7447
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTALLIZATION
DEFECTS
ORIGIN
PHASE STABILITY
RUTILE
STABILIZATION
TITANIUM OXIDES
X-RAY DIFFRACTION