Synthesis of nanometric TiO{sub}2 in aqueous solution by soft chemistry: obtaining of anatase, brookite and rutile with controlled shapes

摘要

Nanometric particles of titania, exhibiting anatase, brookite or rutile polymorphs, were synthesized by thermohydrolysis of TiCl{sub}4 in aqueous medium. The adjustment of physico-chemical parameters (acidity, ionic strength, anions, temperature) allows to tune the crystalline structure, the size and the morphology of the particles. Brookite results from the precipitation of titanium in HCl, HBr or HNO{sub}3 whereas anatase is formed in H{sub}2SO{sub}4 medium. Adding salts in HCl medium leads to ionic strength or complexation effect. Varying the temperature of thermohydrolysis implies modification on yield, size and morphology of the particles.