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Homogeneous Precipitation of TiO 2 Ultrafine Powders from Aqueous TiOCl 2 Solution
Author(s) -
Kim SunJae,
Park SoonDong,
Jeong Yong Hwan,
Park Sung
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb01855.x
Subject(s) - anatase , rutile , precipitation , materials science , aqueous solution , crystallization , phase (matter) , homogeneous , chemical engineering , analytical chemistry (journal) , chemistry , catalysis , thermodynamics , chromatography , photocatalysis , organic chemistry , physics , meteorology , engineering
Crystalline TiO 2 powders were prepared by the homogeneous precipitation method simply by heating and stirring an aqueous TiOCl 2 solution with a Ti 4+ concentration of 0.5 M at room temperature to 100°C under a pressure of 1 atm. TiO 2 precipitates with pure rutile phase having spherical shapes 200‐400 nm in diameter formed between room temperature and 65°C, whereas TiO 2 precipitates with anatase phase started to form at temperatures >65°C. Precipitates with pure anatase phase having irregular shapes 2‐5 µm in size formed at 100°C. Possibly because of the crystallization of an unstable intermediate product, TiO(OH) 2 , to TiO 2 x H 2 O during precipitation, crystalline and ultrafine TiO 2 precipitates were formed in aqueous TiOCl 2 solution without hydrolyzing directly to Ti(OH) 4 . Also, formation of a stable TiO 2 rutile phase between room temperature and 65°C was likely to occur slowly under these conditions, although TiO 2 with rutile phase formed thermodynamically at higher temperatures.