Photoproduction of iodine with nanoparticulate semiconductors and insulators

The crystal structures of different forms of TiO(2 )and those of BaTiO(3), ZnO, SnO(2), WO(3), CuO, Fe(2)O(3), Fe(3)O(4), ZrO(2 )and Al(2)O(3 )nanoparticles have been deduced by powder X-ray diffraction. Their optical edges have been obtained by UV-visible diffuse reflectance spectra. The photocatalytic activities of these oxides and also those of SiO(2 )and SiO(2 )porous to oxidize iodide ion have been determined and compared. The relationships between the photocatalytic activities of the studied oxides and the illumination time, wavelength of illumination, concentration of iodide ion, airflow rate, photon flux, pH, etc., have been obtained. Use of acetonitrile as medium favors the photogeneration of iodine.