Preparation of Nanocrystalline TiO2 Monoliths by Using Modified Supercritical Carbon Dioxide.

0490283 - ÚCHP 2019 RIV NL eng J - Journal Article
Cerhová, Marie - Matějová, L. - Jandová, Věra - Daniš, S. - Dřínek, Vladislav - Sajfrtová, Marie
Preparation of Nanocrystalline TiO2 Monoliths by Using Modified Supercritical Carbon Dioxide.
Journal of Supercritical Fluids. Roč. 137, JUL 2018 (2018), s. 93-100. ISSN 0896-8446. E-ISSN 1872-8162
R&D Projects: GA ČR GA14-23274S
Institutional support: RVO:67985858
Keywords : TiO2 monolith * supercritical carbon dioxide * crystallization
OECD category: Inorganic and nuclear chemistry
Impact factor: 3.481, year: 2018

A flow supercritical fluid crystallization with and without modifier/s was applied to prepare nanocrystalline TiO2 monoliths without subsequent thermal treatment. The effect of processing conditions (temperature, pressure, water concentration, type of modifier: water or ethanol and water) on the crystallization, texture and purity of TiO2 was investigated. It was revealed that one- or multi-step processing by scCO2 with modifier leads to direct crystallization of TiO2 monoliths of anatase-brookite crystal structure even at mild processing temperature of 40°C and 30 MPa. 15 wt.% of water was determined to be the optimal concentration of water in scCO2 as a crystallization agent. Processing temperature affected anatase and brookite crystallite-size. Processing pressure affected crystallization and purity of monolithic TiO2. The pre-drying as well as the post-drying by scCO2 at 40°C visibly improved the solidity of TiO2 monolith and stabilized brookite crystallites.
Permanent Link: http://hdl.handle.net/11104/0284540