Paul Kent Publications

The origin of nanoscale phase stability reversals in titanium oxide polymorphs

Journal of Physical Chemistry C 113 4240 (2009)

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.

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