Photochemical Properties of TiO2 Microcrystallites Prepared in Nafion

Abstract

TiO₂ microcrystallites of different sizes were prepared in Nafion and the energy diagrams of these were determined from the onset potential of photocurrents due to oxidation of tartrate ions and the bandgap energy which was estimated from absorption spectra. The smallest particle prepared in the present study had the diameter less than 2 nm and the bandgap energy of 3.95 eV. Photocatalytic activities of the TiO₂ microcrystallites prepared in Nafion for photodecomposition of acetic acid were very low compared to those of TiO₂ microcrystallites prepared in clay interlayers and were comparable to those of the latter photocatalysts obtained in the presence of SO₄²⁻, suggesting that sulfonate groups of Nafion made the photocatalytic activity of TiO₂ microcrystallites decrease.