High-temperature growth of anatase on kaolinite substrate

0358031 - ÚACH 2011 RIV GB eng J - Journal Article
Rieder, M. - Klementová, Mariana - Szatmáry, Lórant
High-temperature growth of anatase on kaolinite substrate.
Proceedings of the Royal Society A-Mathematical Physical and Engineering Sciences. Roč. 466, č. 2115 (2010), s. 721-730. ISSN 1364-5021. E-ISSN 1471-2946
Institutional research plan: CEZ:AV0Z40320502
Keywords : TiO2 * kaolinite * metastability * photocatalytic activity * X-ray powder diffraction
Subject RIV: CA - Inorganic Chemistry
Impact factor: 1.672, year: 2010

When a fine fraction of kaolinite (less than 2 mu m) is mixed with titanyl sulphate (weight ratio approx. 1 : 7), hydrolysed, washed, dried and heated to temperatures between 750 and 900 degrees C, it transforms into metakaolin, and titania crystallizes as anatase with a small particle size (approx. 20-30 nm). In parallel experiments with plain titania (without kaolinite), rutile is the sole product phase at 850 and 900 degrees C and the dominant phase in a mixture with anatase at 750 degrees C. The particle sizes are much larger (approx. 400-1100 nm). It appears that kaolinite is instrumental in preserving titania in the anatase form and with a small particle size even at fairly high temperatures and hindering its transformation to rutile. However, this anatase exhibits poor photocatalytic activity.
Permanent Link: http://hdl.handle.net/11104/0196177