Photocatalysis of CFC degradation by titanium dioxide

CFC is photodegraded by only hard UV radiation (UV-C) in the upper atmosphere. We have found that fine crystallites of TiO2 catalyse photodecomposition of dichlorodifluoromethane at much longer wavelengths (365-366 nm), which is band gap absorption region of the TiO2 crystallites. Oxidation products detected are fluoride and chloride ions, and chlorine. Experiments are conducted in the gaseous phase, using TiO2 supported on glass plates. Implication of the findings on atmospheric CFC degradation are discussed.