Transformation of Ultrafine Titanium Dioxide Particles from Rutile to Anatase at Negatively Charged Colloid Surfaces
✍ Scribed by Shigeharu Kittaka; Kohsaku Matsuno; Shuichi Takahara
- Book ID
- 102974783
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 876 KB
- Volume
- 132
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
The phase transition of TiO 2 from rutile to anatase has not been reported below the transition temperature from anatase to rutile. This work reports the new observation that ultrafine rutile-type particles are transformed into anatase by contacting the strongly negatively charged colloid particles such as V 2 O 5 • nH 2 O, MoO 3 , and H 2 WO 4 • nH 2 O. The weakly negatively charged particles of silica and montmorillonite did not change the structure. More active Nb 2 O 5 • nH 2 O and Ta 2 O 5 • nH 2 O reacted chemically with TiO 2 to produce new compounds. Conversely, anatase-type TiO 2 was changed into rutile by contacting with HCl solution. From these facts it is concluded that chloride ions at the interface affect to form the rutile-type TiO 2 , although anatase is thermodynamically stable at low temperatures. It is concluded that the surface field of the strongly negatively charged crystalline particles in an acidic condition eases the TiO 2 article to crystallize into a thermodynamically stable one.