PHOTODEPOSITION OF PRUSSIAN BLUE ON TIO2 PARTICLES

It was found that the precipitation of Prussian blue take place uniformly on TiO2 particles in an aqueous ferric-ferri-cyanide solution, accompanied by oxygen evolution, through irradiation of a high pressure mercury arc. Chemical analysis and x-ray diffraction measurements indicated that it consists of a crystalline "insoluble Prussian blue" [Fe4(3+)(Fe(II)(CN)6)3]. The pH of the solution decreased and the amount of O2 increased as the photodeposition of Prussian blue proceeded. Also, electrophoretic measurements suggested that Fe3+...Fe(CN)6(3-) complex adsorbs on the TiO2 particles in the reaction solution. In view of the material balance of the reaction and the results of the electrophoretic measurements, a possible mechanism of the Prussian blue photodeposition was proposed.