Improvement of photocatalytic behavior of chemical-vapor-synthesized TiO2 nanopowders by post-heat treatment

Anatase-type TiO2 nanopowders less than 10 nm in average diameter were synthesized by a chemical vapor synthesis method. The TiO2 nanopowders showed very poor photocatalytic properties, in spite of their large surface area. With subsequent heat treatment of the TiO2 powders, their photocatalytic properties determined by measuring the degradation of 2-propanol were improved at temperatures up to 600 °C and then diminished along with formation of a rutile phase. This improvement in the photocatalytic properties of TiO2 nanopowders was attributed to both a morphology change and a change in the electronic surface characteristics of TiO2 particles during heat treatment.