Pressure-induced amorphization and polyamorphism in one-dimensional single crystal TiO2 nanomaterials

The structural phase transitions of single crystal TiO2-B nanoribbons were investigated in-situ at high-pressure using the synchrotron X-ray diffraction and the Raman scattering. Our results have shown a pressure-induced amorphization (PIA) occurred in TiO2-B nanoribbons upon compression, resulting in a high density amorphous (HDA) form related to the baddeleyite structure. Upon decompression, the HDA form transforms to a low density amorphous (LDA) form while the samples still maintain their pristine nanoribbon shape. HRTEM imaging reveals that the LDA phase has an {\alpha}-PbO2 structure with short range order. We propose a homogeneous nucleation mechanism to explain the pressure-induced amorphous phase transitions in the TiO2-B nanoribbons. Our study demonstrates for the first time that PIA and polyamorphism occurred in the one-dimensional (1D) TiO2 nanomaterials and provides a new method for preparing 1D amorphous nanomaterials from crystalline nanomaterials.

💡 Research Summary

The authors investigated the high‑pressure behavior of single‑crystal TiO₂‑B nanoribbons, a one‑dimensional (1D) TiO₂ polymorph composed of corrugated TiO₆ octahedral sheets. The nanoribbons were synthesized hydrothermally, yielding uniform ribbons 50–200 nm wide, ~20 nm thick, and tens of micrometers long, and were confirmed to be single‑crystalline TiO₂‑B grown along the