| Abstract:
Titania is one of the best-known photo-catalysts. Its photocatalytic properties can be improved by coating on silica spheres and using an additive. In this study, titania sol was separately synthesized by colloidal and polymeric methods. Titanium tetra-isopropoxide, isopropanol, cerium nitrate, deionized water; nitric acid and chloride acid were used as precursors for the preparation of titania sols. Cerium-doped titania sols were prepared with Ce/Ti molar ratios of 0. 05, 0. 1 and 0. 15 using two different methods and then their properties were investigated. The properties of the samples were evaluated using X-ray diffraction and scanning electron microscopy. The photocatalytic activity of titania-ceria composites was evaluated using methylene blue photo-degradation by ultraviolet waves. Removal ability of methylene blue from aqueous solution was also determined by ultraviolet spectroscopy. According to the results, the titania-ceria composites synthesized through the polymeric method showed better photocatalytic activity than the pure titania. Photocatalytic efficiency increased from 67. 39% for pure polymeric titania to 81. 39% for cerium-doped polymeric titania with a molar ratio of Ce/Ti equal to 0. 05. The photocatalytic efficiency of samples with Ce/Ti molar ratio of 0. 1 and 0. 15 was calculated to be 80. 25% and 79. 34%, respectively. Also, the colloidal titania-ceria composites exhibited more photocatalytic activity than pure titania in the early stages of radiation.
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