Alkoxide‐Derived Titania Particles: Use of Electrolytes to Control Size and Agglomeration Levels

Methods of controlling the size and morphology of particles precipitated from the hydrolysis and condensation of tetraethyl orthotitanate (TEOT) in aqueous ethanol solutions through the addition of electrolytes are described. The precipitates display great sensitivity to agitation where, above a critical shear rate, agglomerated morphologies are observed. For reactions carried out at shear rates less than the critical value, narrow size distribution, spherical titania particles are formed under conditions where the particles have electrophoretic mobilities greater than 0.2 × 10 −8 m 2 · V −1 · s −1 for 0.05 M < [TEOT] < 0.2 M and 0.15 M < H 2 O < 0.9 M . Addition of HCl and NaCl to the precipitation solution increases particle charge and expands the TEOT, H 2 O concentration ranges where uniform particles are formed.