Effect of hydrolysis rate on the properties of TiO2-CNT nanocomposite powder prepared by sol-gel method

Abstract

In this study, TiO₂-10%wt. carbon nanotube (CNT) nanocomposite powders were synthesized by sol-gel method at various hydrolysis rate affected by different reaction agents of acetyl acetone and benzyl alcohol. Crystallization of TiO₂ was then achieved through calcination at 400 °C. The properties of nanocomposite powder investigated by scanning electron microscopy, X-ray diffraction and diffuse reflectance spectroscopy. The results showed that, the crystalline TiO₂ with anatase structure was produced after calcination. The crystallite size of TiO₂ depended on the hydrolysis rate which was increased from 25 nm at higher hydrolysis rate by benzyl alcohol to 55 nm at slower hydrolysis rate by acetyl acetone. Before calcination, the results have shown that the slower hydrolysis rate yields relatively large particles with a plate like morphology in contrast to the presence of small particles with significant agglomeration at higher hydrolysis rate by benzyl alcohol. After calcination, high hydrolysis reaction through the use of benzyl alcohol offers easy access to the TiO₂-10%wt. CNT nanocomposite with well controlled coating and desirable interactions between TiO₂ and the CNTs. The thickness of TiO₂ coating on CNTs in this way was 80 nm. Also, TiO₂ particle size depended on the hydrolysis rate, decreased from 1 μm in presence of acetyl acetone to 150 nm in presence of benzyl alcohol. The band gap energy at higher hydrolysis rate by benzyl alcohol was 2.95 eV.