Hydrothermal synthesis of nanosized anatase and rutile TiO2 using amorphous phase TiO2

Citation
Hb. Yin et al., Hydrothermal synthesis of nanosized anatase and rutile TiO2 using amorphous phase TiO2, J MAT CHEM, 11(6), 2001, pp. 1694-1703
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
JOURNAL OF MATERIALS CHEMISTRY
ISSN journal
0959-9428 → ACNP
Volume
11
Issue
6
Year of publication
2001
Pages
1694 - 1703
Database
ISI
SICI code
0959-9428(2001)11:6<1694:HSONAA>2.0.ZU;2-D
Abstract
Phase-pure TiO2 nanocrystallites with narrow particle-size distributions we re selectively prepared by hydrothermal processes starting from amorphous T iO2. Autoclaving amorphous TiO2 in the presence of HF and HCl as cooperativ e catalysts led to the formation of narrow-sized anatase TiO2 with a regula r crystalline surface. Use of nitric acid as a cooperative catalyst with HF also gave the anatase TiO2 with a narrow size distribution but with a rath er irregular crystalline surface. On the other hand, amorphous TiO2 was con verted to phase-pure rutile TiO2 nanocrystallites by autoclaving in the pre sence of citric and nitric acids. Chelation of TiO6 octahedra with citric a cid and acidification with nitric acid are critical for the phase transitio n from amorphous to rutile. The shape of all rutile nanocrystallites was ro d-like. The crystal growth of TiO2 to phase-pure anatase or rutile was prop osed to proceed via respective face-sharing and edge-sharing processes thro ugh dissolution-precipitation of the dissolved TiO6 octahedra from the amor phous phase. The photocatalytic activity in the redox reaction of 2-propano l with oxygen was quite comparable among the synthesized anatase and rutile nanocrystallites.