Abstract
Ti(OPr
i)
4 vapor was pyrolyzed in dry nitrogen atmosphere using a simple tubular flow reactor at 400 and 800 °C. Well-defined spheroidal anatase TiO
2 particles showing mesoporous surfaces of 30 m
2 g
−1 and assuming two different morphologies (fused and composite) were produced at the low temperature (ca. 400 °C), whereas deformed spheroidal particles of rutile-structured TiO
2 and surfaces of 12 m
2 g
−1 were obtained at the high temperature (ca. 800 °C). Particles of the high-temperature product were distinguished by a low porosity and a uniform morphology (composite). The heat-induced modifications at 800 °C may be ascribed to enhancements in
1.
(a) hydrolysis of Ti(OPr
i)
4, by a possible generation of water vapor as a secondary pyrolysis product of the alkoxide.
2.
(b) particle growth via coalescence rather than by vapor deposition, and
3.
(c) particle sintering.
The pyrolysis products were characterized by X-ray diffractometry, high-resolution transmission electron microscopy, and volumetry of nitrogen adsorption at liquid nitrogen temperature.