Optimization of experimental conditions based on Taguchi robust design for the preparation of nano-sized TiO₂ particles by solution combustion method

This investigation was aimed at preparing nanocrystalline TiO₂ powder by solution combustion method, and searching the optimum preparing conditions by employing Taguchi robust design method. Taguchi robust design method with L₁₈ orthogonal array was implemented to optimize experimental conditions for preparing nano-sized titania particles. Titanium IV n-butoxide was hydrolyzed to obtain titany1 hydroxide [TiO(OH)₂], and titanyl nitrate [TiO(NO₃)₂] was obtained by reaction of TiO(OH)₂ with nitric acid. Finally, the aqueous solution containing titanyl nitrate [TiO(NO₃)₂] and a fuel, glycine, were mixed and combusted to obtain the nano-sized titania. The optimum conditions obtained by this method are as follows (based on 1 mol of TiO₂ per batch): concentration of HPC, 0.053 mg cm^-3; mole ratio of Ti:H ₂O:IPA, 1:4:10; hydrolysis time, one hr; the amounts of HNO ₃ and glycine are 10 ml and 0.5 g, respectively; nitrated temperature, 298 K and nitrated time, 2 h. TiO₂ nanocrystalline (∼15 nm) with high BET surface area (350 m² g^-1) and narrow band gap energy (2.7 eV) were thus obtained.