High-pressure crystallisation of TiO2 nanoparticles

The full atomistic structure of a TiO2 nanocrystal, about 7 nm in diameter and comprising 16,000 atoms, has been generated using simulated melting and crystallisation, performed under high-pressure. Specifically, the nanoparticle was heated to 6000 K after which the molten nanoparticle was crystallised at 2000 K under 20 GPa pressure. The resulting nanocrystal comprises rutile- and alpha-PbO2-structured domains (alpha-PbO2 has been identified experimentally as a high-pressure phase of TiO2) expresses (111), (010), (001), and (110) surfaces facilitating a polyhedral morphology and includes grain-boundaries and grain-junction. Molecular graphics images of the various microstructural features are presented together with snapshots of the crystallisation.