Effect of temperature on the physical, optical and photocatalytic properties of TiO 2 nanoparticles

In this paper we describe the effect of calcination temperature on the structural, morphological, optical and photocatalytic properties of TiO 2 nanoparticles. The titanium dioxide powders were produced by the sol–gel method starting from titanium tetraisopropoxide (TTIP) in neutral aqueous medium (pH 5.5). After that, the TiO 2 nanoparticles were treated at three different calcination temperatures for 4 h: 100, 450 and 800 °C. Then, the powders were characterized by XRD, Raman and photoluminescence techniques. We observed the anatase phase for the powders treated at 100 and 450 °C and rutile for that treated at 800 °C. The photocatalytic activity of the TiO 2 powders was investigated using Methylene Blue test and showed a strong correlation with the temperature (i.e. TiO 2 phase). The better photocatalysis exhibited by the nanoparticles treated at 100 and 450 °C compared to the powder at 800 °C was due to the higher recombination of photo-generated electrons and holes of rutile with respect to anatase. Graphic abstract