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Title: Thermal stability of titanate nanorods and titania nanowires formed from titanate nanotubes by heating

The structure of titanate nanowires was studied by a combination of powder X-ray diffraction (XRD) and 3D precession electron diffraction. Titania nanowires and titanate nanorods were prepared by heating of titanate nanotubes. The structure of final product depended on heating conditions. Titanium nanotubes heated in air at a temperature of 850 °C decomposed into three phases — Na{sub 2}Ti{sub 6}O{sub 13} (nanorods) and two phases of TiO{sub 2} — anatase and rutile. At higher temperatures the anatase form of TiO{sub 2} transforms into rutile and the nanorods change into rutile nanoparticles. By contrast, in the vacuum only anatase phases of TiO{sub 2} were obtained by heating at 900 °C. The anatase transformation into rutile began only after a longer time of heating at 1000 °C. For the description of anisotropic XRD line broadening in the total powder pattern fitting by the program MSTRUCT a model of nanorods with elliptical base was included in the software. The model parameters — rod length, axis size of the elliptical base, the ellipse flattening parameter and twist of the base could be refined. Variation of particle shapes with temperature was found. - Highlights: • Titanate nanotubes changed to particles of TiO{sub 2} and nanorodsmore » of Na{sub 2}Ti{sub 6}O{sub 13} at 850 °C. • With heating time and temperature nanorods transformed to rutile nanoparticles. • X-ray diffraction powder pattern fitting indicated an elliptical shape of nanorod base. • No transition of titanate nanotubes to Na{sub 2}Ti{sub 6}O{sub 13} was found after heating in vacuum. • Heating of titanate nanotubes in vacuum leads to appearance of anatase nanowires.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [1]
  1. Charles University, Faculty of Mathematics and Physics, Dept. of Condensed Matter Physics, Prague (Czech Republic)
  2. Stockholm University, Dept. of Materials and Environmental Chemistry, SE-106 91 Stockholm (Sweden)
  3. Charles University, Faculty of Mathematics and Physics, Dept. of Physics of Materials, Prague (Czech Republic)
  4. Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague (Czech Republic)
Publication Date:
OSTI Identifier:
22403599
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 98; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; ANISOTROPY; ELECTRON DIFFRACTION; HEATING; LINE BROADENING; NANOPARTICLES; NANOTUBES; NANOWIRES; PHASE STABILITY; PHASE TRANSFORMATIONS; POWDERS; PRECESSION; RUTILE; TITANATES; TITANIUM; TITANIUM OXIDES; X-RAY DIFFRACTION