The effect of pH on the nucleation of titania by hydrolysis of TiCl₄

Abstract

We have proposed and experimentally tested a phenomenological model of nucleation of a specific polymorphic phase of titanium dioxide (anatase, rutile, brookite) resulting from the interaction of Ti 4+ hydroxocomplexes at different pH values of reaction medium. The degree of hydrolysis was determined as a function of pH for the monomers formed during the hydrolysis of titanium tetrachloride. Mixtures of anatase and brookite with an average size of coherently scattering domains of 5 nm and particles of ellipsoidal shape were obtained by precipitation at pH = 8. At the same time, nanoparticles of rutile with rod-like morphology and an average size of 10 nm were obtained at a pH = 1.

The Effect of Sulphate Anions on the Ultrafine Titania Nucleation

“…We can suggest the following model of SO 4 2− impact on titania nucleation at the stage of olation interaction between primary hydrocomplexes taking into account the results shown in [22]. The hydrolysis of TiCl 4 leads to [Ti(OH 2 ) 6 ] 4+ formation where Ti 4+ ions are in the octahedral coordination with the next transformation to [Ti(OH) h (OH 2 ) 6−h ] (4−h)+ monomers as a result of deprotonation.…”

Ultrafine β-FeOOH: the Influence of Synthesis Conditions on the Morphological, Magnetic and Electrochemical Properties

“…We can suggest the following model of precursor's molarity impact on of iron oxy-hydroxides nucleation. The first stage of the material synthesis involves the FeCl3•6H2O salts hydrolysis and [Ti(OH2)6] 4+ monomers formation where Fe 3+ ions are in the octahedral coordination [13]. Applying the partial charge theory [14], the hydrolysis ratio h for monomers [Fe(OH)h(OH2)6-h] stability are violated.…”

Photocatalytic Properties of Sn-doped TiO2

“…Undoped and Sn-doped titania powders were synthesized using sol-gel method. The initial sol was prepared by hydrolysis of titanium tetrachloride as a titania precursor and tin tetrachloride as a source of Sn dopant [13,14]. Undoped TiO2 was synthesized as a control sample.…”