Thermal decomposition of a peroxopolytitanic acid cryogel: TA/MS study

Thermal decomposition of a peroxopolytitanic acid cryogel was followed by simultaneous thermal analysis (TG/DTA) coupled with mass spectrometer (MS) and infrared spectroscope (FTIR). During the decomposition, the evolution of H2O (either residual moisture or as product of dehydration reactions), NH3 (precipitating agent used in preparation), O2 (decomposition of peroxogroups), SO2 (decomposition of residual sulfates), N2 (freezing agent in preparation), N2O, NO, NO2 (products of NH3 oxidation) and CO2 (adsorbed from atmosphere) was sought for. It was determined, that the decomposition is a four step process. During the first step, water and carbon dioxide evolve. At around 300 °C both N2O and CO2 (m/z = 44) were detected, as confirmed by FTIR spectroscopy. At 430-450 °C (depending of heating rate) amorphous phase crystallizes into anatase.