Visible-Light Sensitive Photocatalytic Activity of FeO<i><sub>x</sub></i>- and P-Modified TiO<sub>2</sub> with Rutile Structure

Nanocrystalline rutile TiO 2 particles were prepared via hydrothermal treatment of Ti-containing precursors obtained by low-temperature aging for a transparent diluted HCl solution of amorphous TiO 2 . The products were modified with FeO x and phosphoric acid, and the photocatalytic activities of the obtained catalysts under visible-light irradiation were examined. By the addition of FeO x or phosphoric acid, the photocatalytic activity of the rutile TiO 2 was slightly increased. On the contrary, by the FeO x loading and subsequent addition of phosphoric acid, significant increases in the photocatalytic activity were attained. Results of UV-vis suggest that the iron oxides formed on the surface of rutile TiO 2 were changed into highly dispersed iron phosphate species by the addition of phosphoric acid. It was presumed that these species effectively suppress the recombination reaction between the photogenerated electrons and holes and contribute to the high photocatalytic activity of the rutile TiO 2 photocatalysts modified with FeO x and phosphoric acid.