pH Effect on Titania‐Phase Transformation of Precipitates from Titanium Tetrachloride Solutions

Precipitates in different structures were prepared by the hydrolysis of a TiCl 4 solution at room temperature and 70°C. The pH effect on titania‐phase transformation was investigated. The original precipitate formed by the hydrolysis of titanium tetrachloride formed a gel‐like structure at pH 4 with the addition of NH 4 OH, which could be changed to essentially 100% rutile phase at 600°C. The rutile precipitates prepared at 70°C could be changed to mixed‐phase product at pH 0.50 and total anatase phase at pH 3.13 and 5.15. Complete phase transformation from anatase to rutile occurred in the three samples at 700°C.