Remote Oxidation of Organic Compounds by UV-Irradiated TiO₂ via the Gas Phase

The remote oxidation of organic materials via the gas phase was studied in detail. A TiO 2 -coated glass plate was faced to an organic film separated by a small gap (50 μm to 2.2 mm), and the TiO 2 was irradiated with UV light. As a result, aromatic and aliphatic substances were oxygenated and decomposed to generate CO 2 by active oxygen species that were generated at the TiO 2 surface and transported in the gas phase. The amount of CO 2 generated during the irradiation with 1 mol of photons was estimated to be 2 × 10 -4 mol for polystyrene oxidation and 3 × 10 -5 mol for polyethylene oxidation. The active oxygen species that oxidizes the organic substrates is most likely to be HO • . Strong evidence for this is the result that the organic materials were oxidized by chemically generated HO • in a similar way.