Abstract
Anatase TiO
2 has been prepared by mechanochemical synthesis using TiOSO
4·
xH
2O and Na
2CO
3 as starting reactants. The reaction was performed in high-energy ball mill using steel and corundum jars, respectively. The final products were obtained by annealing the milled powder in the temperature range of 300–700
°C and subsequently by washing out the water-soluble byproduct Na
2SO
4·
xH
2O. When steel jars were used, the annealing in the range of 300–600
°C led to anatase. For products milled in corundum, the stability of anatase increased up to 700
°C. Transition electron microscopy (TEM) showed that crystallites with a size in the range of 20–50
nm with equiaxed morphology were obtained after milling in corundum and annealing at 600 and 700
°C. The process of photoinduced reactive hydroxyl radical generation in aerated aqueous titania suspensions was studied by EPR spectroscopy using spin trapping technique. The presence of iron impurities in the samples milled in steel substantially decreases the radical formation. The rate of radical formation is substantially affected by particle size development of TiO
2 nanopowders. The product milled in corundum and annealed at 700
°C outperforms more than twice the photochemical activity of TiO
2 Degussa P25 standard.