Effects of preparation parameters on the characteristics of SiO2- and CoxOy-modified-TiO2 colloids prepared by hydrolysis of titanium alkoxide

Anton S. Brichkov, Victiria Yu Brichkova, Evgeniy A. Paukshtis, Yu Wen Chen, Vladimir V. Kozik

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Abstract

A series of SiO2-, and CoxOy-modified-TiO2 colloids prepared by hydrolysis of titanium alkoxide were synthesized. The effects of concentrations of water, acid, cobalt chloride, and tetraethoxysilane on the characteristics of colloids were investigated. The rheologic characteristics of the sols were characterized by liquid state 29Si nuclear magnetic resonance (NMR), Raman spectroscopy, and photon correlation spectroscopy. It was found that an increase in the acid concentration from 1 to 60 mM resulted in a decrease of the particle size from 17 to 9 nm, while the diffusion coefficient increased with twofold. The presence of water shortened the formation time of sol, and the specific concentration of hydrochloric acid stabilized the colloid system. The presence of Co(II) chloride enhanced the hydrolysis rate of tetraethoxysilane and the condensation rate of hydroxy derivatives. In contrast, Ti(IV) tetra-n-butoxide showed the opposite effect, slowing these processes and decreasing the degree of condensation of siloxane chains. The results of this study can be used to optimize the composition of stable homogeneous solutions to synthesize TiO2, TiO2–SiO2, TiO2–CoxOy, and TiO2–SiO2–CoxOy sols. [Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)607-615
Number of pages9
JournalJournal of Sol-Gel Science and Technology
Volume94
Issue number3
DOIs
StatePublished - 1 Jun 2020

Keywords

  • Si NMR
  • Aging time
  • Hydrolysis
  • Sol–gel method
  • Titanium tetra-n-butoxide
  • Viscosity

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