Nanocrystalline TiO₂ by three different synthetic approaches: A comparison

Abstract

A comparison of the efficiency of three different synthetic routes viz. sol-gel method involving templating, mechanochemical synthesis and combustion synthesis for the production of nanostructured TiO₂, is reported. In the sol-gel method, nanocrystalline TiO₂ is produced when titanium tetraisopropoxide is templated onto dodecylamine which forms the liquid crystalline hexagonal structure and the template is then extracted using 1:1 solution of ethanol-hydrochloric acid mixture. Mechanochemical synthesis of nanocrystalline TiO₂ involved mechanical milling of stoichiometric amounts of titanium and cupric oxide in a planetary ball mill using stainless steel vial with wear resistant stainless steel balls. Nanocrystalline TiO₂ is produced by the combustion reaction involving titanyl nitrate and fuels like glycine and citric acid. Nanostructured TiO₂ with an average particle size of ∼ 14 nm is produced by the sol-gel method whereas the mechanochemical reaction between titanium and cupric oxide resulted in the formation of nanocrystalline TiO₂ with an average particle size of ∼20 nm after 12 h of milling. On the other hand, combustion synthesis resulted in the formation of nanocrystalline TiO₂ with an average particle size of less than ∼50 nm. The microstructures of nanocrystalline TiO₂ produced by the above three methods are analysed.