0380909 - ÚCHP 2013 RIV GB eng J - Journal Article
Matějová, Lenka - Matěj, Z. - Fajgar, Radek - Cajthaml, Tomáš - Šolcová, Olga
TiO2 Powders Synthesized by Pressurized Fluid Extraction and Supercritical Drying: Effect of Water and Methanol on Structural Properties and Purity.
Materials Research Bulletin. Roč. 47, č. 11 (2012), s. 3573-3579. ISSN 0025-5408. E-ISSN 1873-4227
R&D Projects: GA ČR GP104/09/P290
Institutional support: RVO:67985858 ; RVO:61388971
Keywords : oxides * sol-gel chemistry * X-ray diffraction
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 1.913, year: 2012

Pressurized water extraction followed by sub/supercritical methanol drying was used for synthesis of TiO2 from gels prepared by sol–gel technique using Triton X-114 like template. It was proved that pressurized water causes titania crystallization. Subsequent sub/supercritical methanol drying is responsible for total elimination of the rest of organic phase originating from the template. The impact of temperature and pressure modifications on titania purity was more essential for pressurized water extraction. The specific surface area significantly increases with removal of the residual organic phase. Anatase was a dominant crystalline phase. The fraction of minor brookite was in the range 20–30 wt.%. In situ XRD showed stability of titania crystallites size up to 300 8C and the presence of brookite crystallites even up to 600 8C. The correlation between Raman FWHM and XRD crystallite size was not influenced by the presence of organic phase and was more sensitive for anatase Eg band 647 cm-1.
Permanent Link: http://hdl.handle.net/11104/0215380