Preparation of nanocrystalline titania powder via aerosol pyrolysis of titanium tetrabutoxide

Abstract

Nanocrystalline titanium dioxide was prepared via aerosol pyrolysis of titanium alkoxide precursor at 200-580°C in air and in nitrogen atmospheres. Powders were characterized by x-ray diffraction, thermogravimetric analysis, Brunauer-EmmettTeller analysis, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, x-ray fluorescence, Raman and infrared spectroscopy, and Berner-type low-pressure impactor. The anatase phase transition was initiated at 500°C in nitrogen and at 580°C in air. Under other conditions amorphous powders were observed and transformed to nanocrystalline TiO 2 via thermal postannealing. In air, smooth and spherical particles with 2-4-m diameter were formed with an as-expected tendency to convert to rutile in the thermal postannealings. In nitrogen, a fraction of the titanium tetrabutoxide precursor evaporated and formed ultrafine particles via the gas-to-particle conversion. At 500°C thermally stable anatase phase was formed in nitrogen. A specific surface area as high as 280 m 2 g −1 was observed for an as-prepared powder.

Effect of SnO2 addition on phase transformation of TiO2 photocatalyst prepared by sol-gel method

“…Experimentally, the critical size of the anatase-to-rutile phase transformation has been reported in the range of 14 ~ 50 nm [11][12], as the size was found to depend on parameters such as temperature [13], impurities [14], and reaction atmosphere [15]. Our experiments indicate that the doping SnO 2 accelerate the anatase-to-rutil phase transformation process via the substitution of Sn 4+ for Ti 4+ .…”

Energetics of nanocrystalline TiO 2

“…The anatase-rutile transformation depends on impurities, grain size, reaction atmosphere, and synthesis conditions (26)(27)(28)(29)(30)(31). Zhang and Banfield (26) reported that the anatase-rutile phase transformation occurred at higher temperature with the addition of Al 2 O 3 .…”

Strained structure of differently prepared amorphous TiO2 nanoparticle: Molecular dynamics study

“…Zhang et al 4 measured microRaman spectra of nanosized TiO 2 powder prepared by vapor hydrolysis. Ahonen et al 5 observed that anatase synthesized in air transformed to rutile at 973 K, whereas anatase synthesized in nitrogen persisted up to 1173 K, and phase transformation is also affected by the interface nucleation and the presence of impurities. [6][7][8] Wang et al 9 and Nakade et al 10 synthesized rutile and anatase TiO 2 by chemical solution method, and Wu et al 11 did sol-hydrothermal synthesis to produce nanoparticles of TiO 2 .…”