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Licensed Unlicensed Requires Authentication Published by De Gruyter December 8, 2016

Preparation of Crystalline Nanosized Titania by Microemulsion: Evaluation of Process Variables

  • Cheng-Di Dong EMAIL logo , Yu-Ling Liao , Chih-Ming Kao , Chiu-Wen Chen , Hong-Yin Lin and Chin-Pao Huang

Abstract

Crystalline TiO2 nanoparticles were synthesized by hydrolysis of titanium (IV) isopropoxide (TTIP) in the docusate sodium salt (AOT) -cyclohexane microemulsion at controlled temperature. The influence of various reaction conditions, such as agitation speed (ε), [AOT]/[H2O] molar ratio (W), [TTIP]/[H2O] molar ratio (R), temperature (T), and aging (t) on the particle size were investigated. The nano-TiO2 particles were characterized for specific surface area (Brunauer-Emmett-Teller, BET) in addition to X-ray diffraction (XRD) and X-ray spectroscopy (XPS) as to determine the particle size, crystalline state, chemical composition, surface charge, and binding energy. The photocatalytic activity was assessed using methylene blue as probe. Results showed that the particle size was in the range from 13.7 to 31.4 nm based on BET measurements. The size of the particle grows with agitation speeds until log (ε) = 1.9; further increase in mixing rate caused particle breakup. In micelle solution, the particle size decreased with increase in W. In true solution the particle size increased with W. However, increase in R increased the particle size which reached a maximum value at a critical value of log R = -0.26, then decreased upon further increase in R. The activation energy (Ea) was calculated using Arrenhius plot and a value of -3.69 kJ/mol was obtained. Results of particle size analysis from XRD and BET were consistent with each other. Crystalline pattern was proved to be anatase. Furthermore, the photocatalytic activity appeared to optimum with particle size between 22.0 and 25.1 nm.

Received: 2007-2-14
Accepted: 2007-4-27
Published Online: 2016-12-8
Published in Print: 2007-7-1

© 2016 by Walter de Gruyter Berlin/Boston

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