Synthesis of Uniform Anatase TiO_2 Nanoparticles by Gel-Sol Method

摘要

The mole fractions of hydroxo complexes of titanium(IV) ion in an aqueous solution with 0.10 mol dm~(-3) NaClO_4 at 25 deg C have been determined as a function of pH by a newly developed analytical procedure based on UV spectrophotometry, using a metastable homogeneous solution 1.25 X 10~(-4) mol dm~(-3) in total concentration of Ti(IV). Also, the total concentration of the hydroxo complexes in equilibrium with Ti(OH)_4 solid, or the solubility of Ti(OH)_4 solid in an inhomogeneous system, has been obtained by ICP measurement for the solution phase. A combination of hese data yielded the absolute concentration of each complex species in equilibrium with Ti(OH)_4 solid. Finally, Ti(OH)_3~+ complex has been assigned to the precursor for the formation of anatase TiO_2 nanoparticles transformed from Ti(OH)_4 gel from a comparison between the above equilibrium data and a kinetic study on the formation rate of the anatase TiO_2 particles in the gel-sol system.