TG/DTA-MS studies on titania precursors with low content of organics for porous thin films of TiO2

Madarász, János and Okuya, M. and Varga P., Péter and Kaneko, S. and Pokol, György (2007) TG/DTA-MS studies on titania precursors with low content of organics for porous thin films of TiO2. JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS, 79 (1-2). pp. 479-483. ISSN 0165-2370

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Abstract

Two commercially available nanosized TiO2 colloids and their suspensions in Triton X-100 have been precipitated and dried carefully. The solids obtained have been studied up to 500 degrees C by simultaneous thermogravimetric and differential thermal analysis (TG/DTA) coupled online with quadrupole mass spectrometer for analysis of evolved gases (EGA-MS) in flowing air, nitrogen and helium atmosphere in order to check and model pyrolytic processes taking place at elevated temperature ranges of porous TiO2 layer fabrication techniques. Pure TiO2 (P25, Degussa) has bounded ca. 12% of Triton X-100, which is released in air gradually till 500 degrees C. An other titania sample (TK302, Tayca) originally with organic content showed a total mass loss of 8% including 1.7% of water released till 140 degrees C and an organic part, which is released in two stages. In the first stage at 275 degrees C probable CH3CN is eliminated according to the MS spectra. In the second step, between 300 and 500 degrees C the organic products with ion-fragments not grater then m/z = 120 have occurred, which in air completely burned into water and CO2. Solid sample resulting from TK302 suspended in Triton X-100 showed a total mass loss of 11.7% including 2.1 % of water released till 105 degrees C and an organic part, which is released in three stages up to 500 degrees C. In the second stage, between 265 and 315 degrees C, in air a sudden huge heat evolution has been produced, which overheated the sample with about 35 degrees C. This extraordinary exothermicity is considered as an advantageous factor in improvement of efficiency of titania thin layers in dye sensitized solar cells. (C) 2006 Elsevier B.V. All rights reserved.

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