Transformation of rutile to TiO2-II in a high pressure hydrothermal environment

Kristina Spektor, Dung Trung Tran, Kurt Leinenweber, Ulrich Häussermann

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The high pressure transformation of rutile to TiO2-II with the α-PbO2 structure is known to be kinetically hindered. In this study we show that a hydrothermal environment at 6 GPa and 650 C provides appreciable rates for producing single phase bulk samples of TiO2-II. So obtained TiO2-II was characterized by scanning electron microscopy, powder X-ray diffraction, Raman and Far-IR spectroscopy. The structural properties are identical to TiO2-II from dry transitions. Transmission electron microscopy studies strongly indicate that Ostwald ripening processes play an important role in the hydrothermally assisted transformation and subsequent growth of TiO2-II crystals. TiO2-II is thermally stable to about 550 C. At 600 C the onset of the transformation to rutile is observed. The thermal expansion in the temperature range from room temperature to 500 C is highly anisotropic, virtually affecting only the c unit cell parameter (αc=7.1(2)×10-6 C -1). The pressure-temperature conditions for the hydrothermally assisted transformation of rutile are viable for industrial production settings, and in light of the large technological significance of TiO2, TiO2-II may present an interesting target for large-scale synthesis.

Original languageEnglish (US)
Pages (from-to)209-216
Number of pages8
JournalJournal of Solid State Chemistry
Volume206
DOIs
StatePublished - Sep 13 2013

    Fingerprint

Keywords

  • High pressure polymorphism
  • Hydrothermal synthesis
  • Multi anvil techniques
  • Titania

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Cite this