The soft chemical synthesis of TiO 2 (B) from layered titanates
Abstract
Proton exchange and subsequent dehydration of layered titanates with the formula A2Ti nO 2 n+1 ( A = Na, K, Cs; 3 ≤ n ≤ 6) yield TiO 2 (B) at temperatures below 350°C. In order to elucidate the mechanism of TiO 2 (B) formation, we have characterized these reactions using thermal analysis and crystallographic techniques, and we have examined the effect of different starting materials on the formation of TiO 2 (B). The dehydration proceeds through three distinct steps: an initial topotactic structural condensation, which is endothermic, followed by an exothermic nucleation and growth step that results in the formation of a TiO 2 (B)-like intermediate, and a final, low-energy transformation, which yields TiO 2 (B). The structures of D 2Ti 3O 7 and TiO 2 (B) have been refined from powder neutron diffraction data in order to better understand the relationship between the initial titanate structures and the formation of TiO 2 (B).
- Publication:
-
Journal of Solid State Chemistry France
- Pub Date:
- December 1992
- DOI:
- 10.1016/0022-4596(92)90184-W
- Bibcode:
- 1992JSSCh.101..275F