Pyrolysis study of sol-gel derived TiO2 powders -: Part IV.: TiO2-anatase prepared by hydrolysing titanium(IV) isopropoxide without chelating agents

An amorphous TiO2 gel was obtained by hydrolysing titanium(IV) isopropoxide with a stoichiometric amount of water using SnCl2 as catalyst. In these operative conditions, a TiO2 gel matrix containing a lower fraction of organic residual was obtained with respect to samples prepared by previously modifying the titanium alkoxide precursor with chelating ligands. Dried gel powders were characterized by N-2 adsorption analyses, FT-IR and XRD measurements. Thermogravimetric (TG) and differential thermal analysis (DTA) coupled with mass spectrometric (MS) and gas chromatographic ( GC) measurements were performed in order to identify the organic products released from TiO2 gel pyrolysis. The TG-MS semiquantitative analysis of the main evolved species allowed to describe both the chemical composition of the initial TiO2 gel and the chemical rearrangements occurring in the matrix during heating up to its crystallisation to anatase form at 420 degreesC.