Novel and facile synthesis of transparent-monolithic TiO2 gels by sol-gel method based on an esterification reaction

• Main Authors: Elghniji Kais, Anna-Rabah Zohra, Elaloui Elimame
• Format: Article
• Language: English
• Published: Sciendo 2016-09-01
• Series: Materials Science-Poland
• Subjects: sol-gel; esterification; tio2; monoliths; transparent
• Online Access: https://doi.org/10.1515/msp-2016-0091

Transparent TiO2 monoliths were obtained through a modified sol-gel route from titanium isopropoxide as a precursor. By controlling the hydrolysis of this precursor through the intermediate of esterification reaction between acetic acid and isopropanol at 40 °C, transparent TiO2 xerogel monoliths were obtained. The monoliths prepared by this method were transparent in the wavelengths between 400 nm and 700 nm. Fourier transform infrared (FT-IR) spectroscopy suggested that the acetic acid played also an active role as a chelating agent, forming Ti[(OH)y(OOCCH3)x] less reactive species. Powder X-ray diffraction confirmed the amorphous-to-anatase phase transformation with the formation of unknown Ti-containing complex at 90 °C. Only anatase TiO2 could be observed in the samples calcined at 250 °C and 450 °C. Optical aspects of the gel (transparent-transluscent transformation of monolithic gel) and gelation time were controlled by changing the amount of external water.