Nanocrystalline TiO2 by three different synthetic approaches:: A comparison

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 similar to 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 similar to 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 similar to 50 nm. The microstructures of nanocrystalline TiO2 produced by the above three methods are analysed.